Men's ASA Slow-Pitch Softball Rules

Boy catching softball

Players of almost any age, from young children to senior citizens, can play slow-pitch softball, and many play in leagues or tournaments governed by Amateur Softball Association of America rules. With a few exceptions -- most notably the pitching technique -- slow-pitch softball is played according to baseball’s standard rules. But it’s the larger, softer ball and the slower pitching that makes the game a cross-generational sport.


At the highest level of slow-pitch softball -- referred to as the “major” level -- bases are 80 feet apart, the pitcher’s rubber is 53 feet from home plate and the outfield fences are between 300 and 325 feet from the plate. On most men’s softball fields, however, bases are 65 feet apart and the rubber is 50 feet from the plate. Outfield fence distances range from 300 to 315 feet.


Legal bats carry an ASA certification label. While wood bats are legal, metal bats are much more common in softball. ASA-certified bats cannot be more than 34 inches long and cannot weigh more than 38 ounces. The standard men’s slow-pitch softball is 12 inches in diameter and also carries an ASA certification label. The ball’s compression -- the pressure required to compress the ball one-quarter inch -- cannot exceed 375 pounds. The ball’s coefficient of restitution, or COR, a measure of the ball’s bounciness, must be .44 or less. For example, a ball thrown at a solid wall at 60 mph will rebound at 26.4 mph if it has a COR of .44.


Unlike fast-pitch softball, the pitcher cannot use a windmill windup. Once the pitcher’s arm passes his hip, he must deliver the ball to the plate. Additionally, the pitch must travel on an arc with a maximum height of 6 to 12 feet. All pitches must be delivered at a “moderate” speed, according to the umpire’s judgment.


Standard slow-pitch softball games are played with 10 fielders. The extra fielder will typically play in the outfield, but teams can place him anywhere in fair territory, as long as he’s not in a position to distract the hitter. Men’s senior leagues may use 11 defensive players. Unlike standard baseball, a player may be removed from the game and re-enter later, provided he bats in his original spot in the lineup.

Game Play

Games are limited to seven innings, unless the score is tied, in which case standard extra inning rules apply.

Teams are limited with respect to over-the-fence home runs, depending on the level of play. At the major level, for example, teams may hit 12 home runs per game over the fence, while low-level Class D players aren’t permitted to hit the ball over the fence. Violation of the home run rule results in an out. Inside-the-park homers are not limited.

A foul ball is always considered a strike under ASA slow pitch rules. A player with two strikes who hits a foul ball strikes out.

Runners may not leave their bases until the pitch reaches home plate. Runners may then attempt to steal second or third base but are not permitted to steal home.