As was the case for the
2006 Classic, several rules were announced for the 2009 tournament that modified the existing rules for international baseball set out by the
IBAF. Once again there were limits on the number of pitches thrown in a game, though the limits themselves were changed from the previous tournament: • 70 pitches in First Round (up from 65 in 2006) • 85 pitches in Second Round (up from 80 in 2006) • 100 pitches in Championship Round (up from 95 in 2006) If a pitcher reached his limit during an at bat, he was allowed to finish pitching to the batter, but was removed from the game at the end of the at bat. A 30–pitch outing needed to be followed by one day off, and a 50–pitch outing by four days off. No one would be allowed to pitch on three consecutive days. As the championship round was played over three consecutive days, a so-called "pitcher rest equalization" rule was added: a pitcher making 30 or more pitches in a semifinal was ineligible to pitch in the final. This negated an advantage the winners of the first semifinal would have had in the final. A
mercy rule came into effect when one team led by either fifteen runs after five innings, or ten runs after seven innings in the first two rounds.
Instant replay was also available to umpires during the tournament. As was introduced in
Major League Baseball during the
2008 season, replays were only used to adjudicate on home run decisions, to determine whether the ball was fair or foul, over the fence or not, and the impact of fan interference. An alternative version of the IBAF's
extra inning rule was also introduced. If after 12 innings the score was still tied, each half inning thereafter would have started with runners on second and first base. The runners would have been the eighth and ninth hitters due in that inning respectively. For example, if the number five hitter was due to lead off the inning, the number three hitter would have been on second base, and the number four hitter on first base. However, this rule was never actually employed in this year's Classic, as the two extra-inning games in the tournament ended prior to a 13th inning. All base coaches were required to wear protective helmets, in the aftermath of the
death of Mike Coolbaugh and participating teams were required to announce the next day's starting pitcher. Additionally, a modified
early termination rule was in effect for the first two rounds; had a team been ahead by 15 or more runs after five innings or ten or more runs after seven or eight innings, the game ended at that point. ==Prize money==