Jack William Armstrong
- Bats Right, Throws Right
- Height 6' 5", Weight 215 lb.
- School University of Oklahoma, Rider College
- High School Neptune High School
- Debut June 21, 1988
- Final Game April 17, 1994
- Born March 7, 1965 in Englewood, NJ USA
Before the All-Star break in 1990, Armstrong went 11-3 for the Reds. He was named the starting pitcher in the All-Star Game, but then only won one more game the rest of the season, against six losses. By the time the post-season rolled around, he had been bounced from the starting rotation, but he did make one appearance in the 1990 World Series, pitching 3 innings of one-hit relief in Game 2, which the Reds won in 10 innings. He was selected by the Florida Marlins in the 1992 Expansion Draft.
He threw a low-90s fastball, a curve and a slider.