"Our game doesn't stop"? Baseball has to have more stalling tactics employed by managers on a game-to-game basis than any other major sport. What a joke.

This seems to me to be a "God of the gaps" argument. You don't know what it is, and you have decided it can't be luck, therefore it must be the GM. You don't have any evidence, you just have a lack of evidence (that any other specific thing is the cause). That doesn't make a strong argument. Forced to choose between those two possibilities, I'd go with luck. But first I'd look for another answer.

McDonald's fielding makes him a replacement player, not a sub-replacement player.