What is a Quality Start?

A quality start is a stat that measures whether a starting pitcher delivered a solid outing. To qualify, the pitcher must throw at least six innings and allow three earned runs or fewer. The idea behind the stat tracks how often a starter gives their team a chance to win. That means making sure the pitcher did not getting shelled or exit early.

Unlike ERA or strikeout totals, quality starts don’t factor in how dominant a pitcher was. It doesn’t matter how many hits, walks, or strikeouts were allowed — as long as the starter goes six and keeps earned runs to three or fewer, it counts. For example, a pitcher can throw six innings, allow three earned runs, and finish with a 4.50 ERA. That still qualifies. On the other hand, five shutout innings wouldn’t meet the requirement.

How is a Quality Start Used?

Quality starts are used to track how often a starting pitcher meets a baseline of effectiveness. The stat shows how many times a pitcher goes at least six innings and allows three earned runs or fewer.

It’s commonly used to evaluate consistency and workload across a season. Pitchers who record a high number of quality starts are often reliable options in a rotation. Teams use the stat to identify which starters regularly give them a chance to compete without overexposing the bullpen.

Quality start totals are also used to compare starters across the league. While the stat doesn’t factor in strikeouts or total runs allowed, it still reflects whether a pitcher handled their assignment and kept the game within reach.

How to calculate Quality Starts?

A quality start is not calculated with a formula like ERA or WHIP. Instead, it’s a yes-or-no stat based on two conditions.

First, the starting pitcher must throw at least six full innings. Anything less, even 5.2 innings, does not qualify.

Second, the pitcher must allow three earned runs or fewer. If they give up four or more, regardless of innings pitched, it does not count.

Both conditions must be met. If one is missed, the outing is not labeled a quality start. The stat is straightforward, no percentages or averages, just whether the outing met the minimum standard.

Quality Start Examples

Paul Skenes (March 27th, 2025 – Pittsburgh Pirates vs Miami Marlins)

https://www.baseball-reference.com/boxes/MIA/MIA202503270.shtml

5.1 IP

2 ER

With this stat line, Paul Skenes wasn’t credited with a quality start despite allowing fewer than three earned runs. Pitching only 5.1 innings kept him from meeting the six-inning minimum required to qualify.

Greg Maddux (August 4, 1995 – Atlanta Braves vs Montreal Expos)

https://www.baseball-reference.com/boxes/MON/MON199508040.shtml

8.0 IP

3 ER

With this stat line, Greg Maddux was credited with a quality start after going 8 innings and allowing 3 earned runs, meeting both requirements for the stat.

Carlos Zambrano (June 27, 2006 – Chicago Cubs vs Milwaukee Brewers)

https://www.baseball-reference.com/boxes/CHN/CHN200606270.shtml

8.0 IP

4 ER

With this stat line, Carlos Zambrano wasn’t credited with a quality start, as he allowed more than 3 earned runs despite pitching 8 innings.

What is a Walk?

A walk, officially known as a base on balls (BB), occurs when a pitcher throws four pitches outside the strike zone and the batter does not swing at any of them. Once ball four is called, the batter is awarded first base. Walks are a core part of evaluating both pitcher control and batter discipline. They don’t count as hits, but they do count as plate appearances and times on base.

Walks don’t impact a hitter’s batting average, but they are included in on-base percentage (OBP), making them valuable in measuring a player’s ability to reach base. For pitchers, a high walk total often points to poor command and control, which can inflate other stats like WHIP and ERA.

How are Walks Used?

Walks are used to evaluate a pitcher’s command and a hitter’s patience at the plate. On the pitching side, limiting walks is a sign of control and efficiency, especially in high-leverage situations. On the hitting side, drawing walks helps boost a player’s OBP and keeps innings alive. Teams value players who can work the count and potentially force pitchers into mistakes. Over the past decade, teams across the league have prioritized players who can consistently get on base, creating more scoring opportunities for the batter at the plate. 

How to Calculate Walks

There’s no formula to “calculate” a walk — it’s a tracked stat recorded every time a batter reaches base via four called balls in a plate appearance. However, Base on Balls percentage (BB%), also known as walk rate, is the advanced stat used to measure walks. It tracks the percentage of a player’s plate appearances that end in a walk. 

Walk Rate(BB%) Formula

Walk Rate (BB%) = (Walks / Plate Appearances) × 100

Walk Examples: 

Juan Soto 2021 – Walk Rate (22.2%) = (145 / 654) × 100

https://www.baseball-reference.com/players/gl.fcgi?id=sotoju01&t=b&year=2021

Barry Bonds 2004 – Walk Rate (37.6%) = (232/617) x 100

https://www.baseball-reference.com/players/gl.fcgi?id=bondsba01&t=b&year=2004

Babe Ruth 1920 – Walk Rate (24.3%) =  (150/617) x 100

https://www.baseball-reference.com/players/gl.fcgi?id=ruthba01&t=b&year=1920

What is a Run Scored in baseball?

A run scored (abbreviated R and also called a run) is credited to a runner that rounds the bases and crosses home plate. A team wins a game by scoring more runs than the opposing team.

How is Run Scored used?

As previously mentioned, runs are crucial in baseball because they determine which team wins a game. They can also be useful in assessing players’ offensive skill. Players with the most runs are often good at getting on base and running the bases. However, players with many runs might also benefit from being near the top of the lineup, which usually features a team’s best hitters.

Runs are also a defensive statistic. Whenever a runner scores a run, a pitcher is also charged with allowing a run. Pitchers with many runs allowed are usually considered bad (unless they have an awful defense that’s responsible for allowing runners to score, which earned run statistics account for).

Run rule in college baseball

In the MLB, the amount of runs scored never determines when a game ends. Games are simply played to 9 innings (or more, if the score remains tied at the end of the 9th inning).

But there is a “run rule” in college baseball (also called the mercy rule). After the 7th inning, if a team is ahead by 10 or more runs, the game can end. Whether or not the run rule applies depends on conference rules, or what the teams’ coaches agree to do.

Run Scored Examples

Sometimes, it is hard to tell whether a play counts as a run. Let’s look at some examples of scenarios in which a runner can or cannot be credited with a run scored.

Out at home plate

If the runner gets caught (usually by the catcher tagging him out) before he can reach home base, he is out. Therefore, he does not score and does not get credited with a run.

Two-out scenarios

What happens when a third out is recorded while a runner is heading for home plate?

If the third out is a force out, the runner cannot score and does not get credited with a run.

If the third out was made before the batter reaches first base, the runner cannot score.

But if the third out is made after the batter safely makes it to first base (for example, the batter is caught trying to get to second base), the runner can score if he crosses home before the out is made.

Interesting Run Scored Stats

You can see the single-season leaders in R, or the career leaders in R on Baseball Reference.

What Is a Save?

A Save is a stat credited to a relief pitcher who finishes a game for the winning team under specific conditions. To record a save, the pitcher must not be the winning pitcher and must meet one of the following requirements:

• Enter the game with a lead of three runs or fewer and pitch at least one full inning
• Enter with the tying run on base, at bat, or on deck
• Pitch the final three innings of the game, regardless of the score

In all cases, the pitcher must be the final pitcher of the game and his team must win. Saves are typically recorded by closers, but any relief pitcher can earn one if the conditions are met.

How Is a Save Used?

The save is used to track how often a relief pitcher finishes a game while preserving a lead. It plays a key role in defining bullpen usage, particularly for pitchers assigned to close out tight games. Closers, who often appear in the ninth inning, typically record the most saves across a season.

Saves also help outline bullpen structure. While setup pitchers can earn holds for maintaining a lead before the final inning, only the last pitcher in a qualifying situation can be credited with a save. If that pitcher allows the lead to slip, it is recorded as a blown save, a related stat used to evaluate late-game performance.

Another stat tied to this is the save opportunity, which occurs any time a pitcher enters the game under save conditions. Regardless of whether the pitcher earns the save or not, the appearance counts toward this total.

Saves are used to compare relief pitchers across seasons and eras. Leaders in saves are often pitchers who consistently appear in close-game scenarios and finish the job. The stat provides a standardized way to assess which relievers were trusted to secure wins when the game was on the line. Closers atop the saves leaderboard are those who consistently deliver in high-leverage situations.

Save Examples

Edwin Díaz (June 12th, 2025 – Washington Nationals vs New York Mets)

https://www.baseball-reference.com/boxes/NYN/NYN202506120.shtml

1.0 IP

S (15)

Edwin Díaz came into the game in the 9th inning with the score being 4–1 Mets. Ryne Stanek left baserunners on first and third, creating a save situation once Díaz entered. After the lead was cut to 4–3, Díaz retired the final two batters to end the game and secure the win. Because he was the final pitcher, his team won, he was not the winning pitcher, and he entered with the tying run on base, Díaz met the conditions for a save and was credited with his 15th of the season.

Josh Hader (June 6, 2025 – Cleveland Guardians vs Houston Astros)

https://www.baseball-reference.com/boxes/CLE/CLE202506060.shtml

1.0 IP

S (15)

Josh Hader came into the game in the 9th inning with a 4–2 lead. In the inning, he retired all 3 batters consecutively with a groundout and two strikeouts. Since he entered with a lead of three runs or fewer, pitched a full inning, was the final pitcher in the game, and was not credited with the win, Hader met all the conditions for a save and was awarded his 14th of the season.

What is a Grand Slam?

A grand slam is a home run hit with the bases loaded. That means there are runners on first, second, and third base when the batter goes deep. It results in four runs scored, the maximum possible on a single play.

Grand slams are among the most impactful moments in a game. Not only does the batter score, but all three base runners do as well. It’s one of the biggest momentum-shifting swings in baseball and often changes the outcome of a game in one swing.

How is a Grand Slam used?

A grand slam is used to measure high-leverage power hitting. It shows a player’s ability to deliver when the bases are loaded and pressure is high. While hitting with the bases loaded is rare on its own, going deep in that opportunity is even rarer — which becomes valuable to any team. Historically, grand slams are a big part of signature games and highlight moments for power hitters.

How to calculate a Grand Slam?

There’s no formula to calculate a grand slam — it’s a result of the situation. It occurs when:

• The batter hits a home run
• The bases are loaded at the time of the swing

All four runs count as earned runs against the pitcher, and the hitter is credited with one home run and four RBIs. Grand slams count the same in the box score as any other home run, but their impact is amplified in certain game situations, thanks to win probability added.

Grand Slam Examples

Some players have hit grand slams, but these players specifically hit theirs during a World Series game:

Addison Russell – Game 6 – 2016 World Series Cubs vs Indians

https://www.baseball-reference.com/boxes/CLE/CLE201611010.shtml

Alex Bregman – Game 4 – 2019 World Series Astors vs Nationals

https://www.baseball-reference.com/boxes/WAS/WAS201910260.shtml

Adam Duvall – Game 5 – 2021 World Series Braves vs Astros

https://www.baseball-reference.com/boxes/ATL/ATL202110310.shtml

What is a Stolen Base?

A stolen base occurs when a baserunner advances to the next base while the pitcher is delivering the ball to home plate, without the help of a hit, walk, error, or passed ball. If the runner reaches safely before being tagged out, it’s recorded as a stolen base (SB). However, if the runner is thrown out, it’s scored as a caught stealing (CS).

Over time, the stolen base has remained one of the most exciting plays in the game. It rewards speed, timing, and instincts — giving teams an opportunity to apply pressure without needing contact from the batter.

How is a stolen base used?

Stolen bases are used to measure a player’s baserunning ability and aggressiveness. Players who steal bases effectively can disrupt pitchers, alter defensive alignments, and put themselves in better scoring position. As a result, managers often lean on base stealers in late-game situations or during close matchups.

In addition to basic counting stats, stolen bases are also used in advanced metrics like stolen base percentage (SB%), which evaluates efficiency rather than just volume. Stolen base percentage (SB%) is calculated by dividing stolen bases by total steal attempts. A higher SB% reflects a runner’s efficiency and value on the bases, not just their speed.

How is a Stolen base calculated?

To record a stolen base, the runner must:

• Attempt to advance to the next base during the pitcher’s delivery
• Reach that base safely without the benefit of a hit, error, or wild pitch
• Not be part of a double steal where another runner is thrown out

Stolen bases can occur on any base, but most often happen from first to second. Runners are not awarded a stolen base if they advance on a passed ball, wild pitch, or defensive indifference.

Stolen Base Examples

Ricky Henderson is the only MLB player ever to have 1000+ stolen bases in their career.

https://stathead.com/tiny/DUIcY

Ronald Acuna in 2023, while hitting 41 home runs, stole 73 bases, making the 40/70 club which had never been done before.

https://stathead.com/tiny/D8eJl

Shohei Ohtani in 2024, became the only player to hit 50 home runs, while stealing 50 bases, making his own 50/50 club which hadn’t been done before.

https://stathead.com/tiny/YdUoo

What is Left on Base in Baseball?

Left on base (LOB) refers to the number of runners a team or player strands on base by the end of an inning. If a baserunner reaches safely but is not driven in before the third out is recorded, they are considered “left on base.”

From a team perspective, LOB shows how many scoring opportunities were missed. From an individual standpoint, it tracks how many runners were left on base during that player’s plate appearances, not necessarily how many they personally stranded.

How is Left on Base used?

Left on base is used to measure offensive efficiency and how well a team capitalizes with runners in scoring position. A high team LOB total can signal missed chances, especially in close games. On the other hand, consistently stranding runners limits run production and puts pressure on pitching and defense.

From a player’s point of view, individual LOB is often used in tandem with other situational stats like batting average with runners in scoring position (RISP) or clutch hitting metrics. Managers and analysts look at LOB to assess whether hitters are converting when it matters most.

How to calculate Left on Base?

Team LOB is calculated by counting the number of runners left on base at the end of each inning.

Individual LOB is credited when a player makes an out while runners are on base, and those runners are not able to score during that inning.

Left on Base Examples

New York Yankees vs New York Mets: July 6, 2025

In the New York Yankees 6-4 win over the Mets, the Yankees left 7 players on bases, while the Mets left 7 players on base as well.

https://www.baseball-reference.com/boxes/NYN/NYN202507060.shtml

Baltimore Orioles vs Kansas City Royals: April 4, 2025

In the Royals 8-2 win over the Orioles, the Royals left 8 players on bases, while the Orioles left 4 players on base.

https://www.baseball-reference.com/boxes/KCA/KCA202504040.shtml

What is a Putout?

A putout (PO) is credited to a defensive player who physically records an out. This can happen in a number of ways: catching a fly ball, tagging a runner, stepping on a base for a force out, or being the receiver on a strikeout. While it’s a simple stat, it’s an essential part of how outs are tracked in the game.

Putouts are recorded on nearly every out in baseball and are used to credit the defensive player directly involved in finishing the play.

How is a putout used?

Putouts help track a fielder’s involvement in defensive plays. While they don’t tell the full story of a player’s range or defensive skill, they do show how often a player is on the receiving end of an out.

For example, first basemen tend to lead the league in putouts because they complete a large number of force plays at first. Catchers also rack up putouts on strikeouts. Meanwhile, outfielders record putouts primarily by catching fly balls.

How to record a putout?

A fielder is awarded a putout in the following situations:

• Catching a fly ball
• Tagging a runner for an out
• Fielding a ground ball and stepping on a base for a force out
• Catching the third strike on a strikeout
• Being closest to a runner called out for interference

Only one player is credited with the putout per out, even if multiple players are involved in the play.

Putout Examples

Milwaukee Brewers vs Miami Marlins – July 4, 2025:

Milwaukee Brewers C William Contreras: 9 Putouts

Miami Marlins C Nick Fortes: 10 Putouts

https://www.baseball-reference.com/boxes/MIA/MIA202507040.shtml

New York Mets vs Arizona Diamondbacks – May 17, 2017:

Arizona Diamondbacks 1B Paul Goldschmidt: 15 Putouts

New York Mets 1B T.J. Rivera: 8 Putouts

https://www.baseball-reference.com/boxes/ARI/ARI201705170.shtml

What is an RBI in baseball?

Runs batted in (commonly referred to as RBI) are given to the batter when runners score due to any hit, fielder’s choice, out, walk or HBP. Each runner who scores in those scenarios counts as 1 RBI for the batter. A batter can also earn an RBI by batting himself in on a home run.

What doesn’t count as an RBI?

Runs that score as the result of double plays (or the rare bases loaded triple play) or errors do not give RBI. Conversely, no RBI is granted on a wild pitch, passed ball, balk or steal of home.

The Runs Batted In controversy

The official statisticians of Major League Baseball only recognize RBI totals from 1920 onward. This may cause confusion, because it cuts off an important chunk of Babe Ruth‘s RBI and leaves out Cap Anson altogether. So in recent years, when Alex Rodriguez and Albert Pujols approached 2000 RBI, there were a number of misleading articles about them “catching” Ruth, or their places on the all-time leaders list.

However, most baseball historians recognize a more comprehensive list that estimates runs batted in for years prior to 1920. Baseball Reference’s list of career leaders, linked at the bottom of this page, is the most reliable one.

How are Runs Batted In used?

RBIs are one of the most commonly tracked offensive statistics in baseball. They tell us how often a batter’s actions result in runs being scored.

However, determining what is an average RBI (or above-average RBI) in baseball is difficult. A player’s batting position and power, and his teammates’ ability to get on base, can all affect runs batted in.

Some of the best hitters can record more than 140 RBI in a season. Anything above 100 is generally considered a good season total RBI.

Runs Batted In Examples

• A team has runners on second and third base. The batter hits a double, and both runners score. The batter earns 2 runs batted in, because his hit resulted in two runners scoring.

• A team has no runners on base, but the batter hits a home run. The batter still earns 1 RBI, because he batted himself in.

• A team has the bases loaded. The batter is hit by a pitch, causing the runner on third to score. The batter earns 1 RBI even though he didn’t get a hit, because the HBP caused a runner to score

• A team has a runner on third. The batter reaches base on an error, and the runner on third advances on the error to score. The batter does not earn an RBI, because the runner scored on an error – not any of his actions.

Interesting RBI Stats

You can see the single-season leaders in RBI, or the career leaders in RBI on Baseball Reference.

What is Earned Run Average?

The definition of earned run average (ERA) is “the number of earned runs a pitcher allows per nine innings.” Earned runs are runs that are scored because of pitching, not bad defense like errors or passed balls.

Most pitchers do not play nine innings in each game. Thus, the earned run average formula takes the number of earned runs allowed in the innings a pitcher did pitch and uses them to calculate how many earned runs he would have allowed, had he pitched nine innings.

How is ERA used?

A pitcher’s ERA is a primary measure of his success. A low ERA indicates that a pitcher is good at limiting his opponent’s scoring. 

Earned run average is particularly useful for evaluating starting pitchers. To earn a perfect 0.00 ERA, a pitcher must not allow any earned runs to be scored. Additionally, if a pitcher allows a hitter to reach base, and then a different pitcher allows him to score, then the pitcher who allowed the runner to reach is charged with the run.

ERA is similar, but not identical to, run average.

Earned Run Average Formula

The earned run average formula is:

ERA = (Earned Runs Allowed / Innings Pitched) * 9

How to calculate Earned Run Average?

Dividing earned runs a pitcher allowed by the number of innings he pitched gives us the average number of earned runs he allowed per inning. Multiplying that by nine (for nine innings) gives us the number of earned runs he was expected to give up over nine innings.

How to calculate the Earned Run Average for one game?

Say a pitcher allows 3 earned runs over 6 innings. Here’s how you would calculate his ERA:

1. Divide his earned runs allowed (3) by the innings he pitched (6). 3/6 = 0.5.
2. Multiply 0.5 by 9. 0.5*9 = 4.5.

The pitcher’s earned run average for that game would be 4.50.

For a real-life example, let’s look at Paul Skenes’ first career start, where he pitched 4 innings and allowed 3 earned runs. Here’s how you would calculate his ERA:

1. Divide Skenes’ earned runs allowed (3) by the innings he pitched (4). 3/4 = 0.75.
2. Multiply 0.75 by 9. 0.75*9 = 6.75.

So Paul Skenes recorded a 6.75 ERA in his first career start.

How to calculate the Earned Run Average for multiple games?

We can also calculate a pitcher’s ERA over multiple games, seasons, or even his entire career. This uses the same earned run average formula that we use to calculate single games.

For example, Cy Young pitched 7356 innings and allowed 2147 earned runs. Here’s how you would calculate his career ERA:

1. Divide his career earned runs allowed (2147) by the number of innings he pitched over his career (7356). 2147/7356 = 0.292.
2. Multiple 0.292 by 9. 0.292*9 = 2.628.
3. Round 2.628 to 2.63, since ERA typically only includes 2 decimal places.

Cy Young’s career ERA is 2.63.

Interesting ERA Stats

You can see the single-season leaders in ERA, or the career leaders in ERA on Baseball Reference.