Going to have to agree with the OP too. It's silly for a reliever to warmup so much that he's tired. This would never happen in real life. Bullpen usage is a BIG part of managing a baseball club, so turning it off detracts a lot from realism.
I'm actually reading LaRussa's book "The Last Strike" (fantastic read) at the moment and he talks a lot about bullpen usage throughout the book. Getting them up, when to bring them in, lefty/righty matchups, setup roles, closer roles, etc. He never once talks about relievers warming up so much that they tire themselves out. Why? Because it doesn't happen!
