OBA & 9U Major Rookie League Rules (Western Ontario Baseball Association)

PrintOBA & 9U Major Rookie League Rules

League Specific Rules (revised 2023)
WOBA OBA & 9U Major Rookie (ages 8 & 9)


  1. 11u Mosquito players may not play on a 9u Major Rookie team.  All overage players must be approved by the WOBA before they are permitted to play for any season or league game on a Major Rookie team.
  2. Umpires and the opposing team coaches must be informed of all overage players (10-year-old mosquito age) prior to the start of the game.
  3. Overage players may not pitch or play at the pitching position.
  4. Closed toe shoes must be worn by all players as well as the operator of the pitching machine.
  5. A regulation "pitching machine" ball or any baseball approved for Mosquito play shall be used.
  6. Each team shall have 10 players (6 infielders/4 outfielders) in the line-up. A team may play as long as it has 9 players at the game. If 8 or less players at a game, the game is forfeited to the other team.  For specifics see OBA Rule RQ2.3(b)
  7. The only coaches that are allowed to be on the field and to coach are the 1st base and 3rd base coaches for the offensive team.
  8. The coach feeding the pitching machine must wear a regulation batting helmet. OBA Rule RQ2.3(x)
  9. Games are 7 innings with no new inning starting after 90 minutes of play and finishing within the 105 minute (1.75 hour) maximum time limit.
  10. Batter will receive up to a maximum of 5 strikes as called by the umpire. OBA Rule RQ2.3(h)
  11. 5th strike is automatically out. The batter shall not be called out if the 5th strike is called a foul ball. OBA Rule RQ2.3(h)
  12. Outfielders must be a minimum of 15 ft behind the bases and base paths.
  13. Base runners cannot leave the base until the batter makes contact with the ball. No lead off permitted. One warning will be issued and for any further infractions thereafter, the runner will be called out.  Each team will receive one warning.
  14. When a batted ball is hit to the outfield the runners may advance to the next base or bases at their own risk until the ball has returned to the infield. If a runner is more than halfway to the next base they may advance with the risk of being thrown out. If they are not halfway, they must return to the base they just occupied without risk of being put out.
  15. Runners are not allowed to steal any base or home.  Runs can only be scored when a ball is batted into play.
  16. An inning will be 7 runs or 3 outs, whichever occurs first.
  17. All players must bat.
  18. No open inning in league play.
  19. No mercy rule.
  20. Coaches have the option to have a courtesy runner for catcher.
  21. Infield fly rule does not apply.
  22. A single white base is to be used at first base only and not a contrast-coloured (orange) double base.
  23. In the event of lightning, play is to cease immediately. The Umpires will instruct resumption of game.
  24. Report game scores via the OneDB www.theonedb.com web-link.
  25. IMPORTANT Report all injuries immediately to Baseball Ontario  www.playoba.ca  Click Safe Sports tab, >Insurance