3B Ump hit by throw from F2 NCAA game

[Manny A]

Originally Posted by AtlUmpSteve

Seems to me the one possible correct answer has been ignored by all.

If the PU interfered with the catcher's pickoff throw, which THEN was muffed by F5, hit the U3, etc., then it would be umpire interference and the runner would be returned to 3B.

I actually thought about that, but when the OP said, "The crew then made R1 return to third base," I assumed there was some sort of pow-wow between the three umpires before the decision was made. If it was interference by the PU, he/she should have killed play when the ball got past F5, and then make the call unilaterally.