I was thinking about IR the other day and was wondering if there would be a penalty for an upheld call, like there is in the NFL. What would it be? An out? A strike? I don't really think you can penalize there. I'd be in favor of 2 calls per game per team, or every call coming at the discretion of the replay official. There would be no penalty in baseball, but the main reason you lose a timeout in football is to prevent the abuse of coaches intentionally throwing the challenge flag on ridiculous plays just to give their defense a break, or just to call an offensive play without a timeout. In baseball, there are many fewer advantages that stalling can get you. and since there are other legal ways to stall, there won't be much advantage gained by the team issuing the challenge if they lose. So there really isn't any penalty necessary. The only thing I can think of is warming up a bullpen pitcher, which could be significant. Umpires already break up meetings between managers and their pitchers anyway -- using a replay "flag" or whatever could just take its place.