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Handedness of Opening Day starters

Posted by Andy on March 18, 2011

In the last 20 seasons, there have been 138 Opening Day games started by left-handed pitchers. Randy Johnson has 14 himself, followed by Mark Buehrle with 8. There have been 444 Opening day games started by righties, led by Roger Clemens with 10 and Brad Radke with 9.

That works out to 23.7% of games started by lefties.

Over the same 20 years, looking at all games (not just Opening Day), lefties have started 25,906 games and righties have started 66,514 games. That's 28.0% of games started by lefties.

That means that lefties are a bit less likely to start on Opening Day than on other days. In turn, this might simply mean that over the last 20 years, there have been a few extra right-handed ace pitchers that have prevented lefties from taking some of those #1 turns.

Going back to 1919 (yes, our box scores go back to 1919 now!) the numbers are:

Opening Day:  508 starts by lefties, 1,444 starts by righties (26.0% by lefties)

All: 88,743 by lefties, 218,857 starts by righties (28.9%  by lefties)

This entry was posted on Friday, March 18th, 2011 at 7:10 am and is filed under Box Scores. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

10 Responses to “Handedness of Opening Day starters”

  1. My guess is that opening day starters more accurately reflects the natural righty-lefty rate. Certainly there will be a higher rate of lefties even there than occur in nature, because lefties are more likely to be encouraged to play baseball and to pitch.

    But guys with ace-level talent are likely to find their way to the top based purely on that, while back of the order guys might make it to the majors because organizations are more eager to develop borderline lefty arms than borderline righty arms.

  2. The box scores go back to 1919 but not the PI

  3. The PI does.

  4. The year box gives 1919 but the results give nothing for that year in any search I have tried

  5. Oh, hmm, let me check for clarification on that.

  6. Looks like the 1919 links are still a bit buggy. That's understandable as they haven't been announced yet, so they might be a work in progress.

  7. Yeah Sean is probably working on it literally right now, as it seems Neil doesn't even know the answer.

    Sometimes Sean announces stuff to us early--for example I have been using the mobile site for several weeks now. But often times, he rolls out stuff without telling us beforehand, or even announcing it at all. Raphy happens to be really good at noticing new features and I often get messages from him saying--hey did you notice this new thing?

  8. The first thing I think of is that many in baseball apparently subscribe to a philosophy that there are fringe benefits to having at least one lefty in the rotation (I think the idea is to change the look that the batter is seeing, but in this age of 5-man rotations, 3-game series and extensive video scouting I'm not sure this is of much value).

    Andy cites numbers showing just over 1/4 of games started by lefties. So in a 4-man rotation about 1 per team and in a 5-man rotation 1.25 per team. With these averages it is easy to see how many teams might have 0 lefties or perhaps find themselves in a situation where they are going to have zero lefties if they don't take a marginal lefty over a marginal righty to fill the last rotation spot. If this were the case often enough we would have lefties over-represented among starting pitchers, but there would be no reason for this bias to carry over to opening day starters because opening day games are almost never started by marginal members of the rotation.

    In fact, there is reason to believe that the opposite might be true. If a manager were having trouble deciding to between a LH and a RH opening day starter and believes in the changing the looks theory he would probably go with pitcher whose handedness matched the pitcher pitching game 3, which is apparently 70+% likely to be a RHP.

  9. DoubleDiamond Says:

    Sometimes, teams like to separate the lefties and righties in the rotation. If a team has two potential #1 guys, one LH and one RH, and the #3 guy is a righthander (which is statistically more likely), then in an opening three-game series, the sequence will be RH-LH-RH.

  10. [...] handed pitcher can be sneaky useful. Best to target those who mash right-handed pitchers, who are nearly three time more likely to start than lefties, since those hitters, by default, will get more opportunities to inflict damage—or if [...]