The NCAA instituted a rule on collisions for the 2011 season, saying "contact above the waist that was initiated by the base runner shall not be judged as an attempt to reach the base or plate." The umpire can call the runner out and also eject the player if contact is determined to be malicious or flagrant.
Drafting the big league rule figures to be complicated.
"Does it include at every base or just home plate?" Baltimore manager Buck Showalter said.
AP Sports Writer Howie Rumberg contributed to this report.