Erstad - Estrada Collision at the plate

[VaUmp]

To GarthB: I don't know much about the Major League Rules but if the following quote from your missive is correct, "
a runner is not allowed to use his hands or arms to commit an obviously malicious or unsportsmanlike act-such as grabbing, tackling, intentionally slapping at the baseball, punching, kicking, flagrantly using his arms or forearms, etc.-to commit an intentional act of interference unrelated to running the bases.", then I can't see why you wouldn't classify dropping a shoulder as "obviously malicious or unsportsmanlike". Now, if the MLB interpretation is that anything goes, it was a legal maneuver.