If you aren't pacing yourself, of course you can come out and go full bore and not worry. Even HWMNBN went to the bullpen and got an extra 3 MPH on his fastball out of the pen, because he wasn't pacing himself to go 6 innings. Fast Eddie Diaz went from 95-97 to 100 when he knew it was max effort for a single inning.
When you are a 300+ pound defensive lineman, and you're basically doing a wind sprint impeded by a 300+ pound offensive lineman, trying to get to Aaron Rodgers, you aren't going to be able to do that very many times in a row before your performance suffers. Micheal Bennett and Cliff Avril both got better once they got here, because they were used properly, not just used up. I daresay Sheldon Richardson will enjoy a similar benefit.