If you have a five man rotation and all of the pitchers in that rotation are true starting pitchers that can go 70+ pitches each start, I'd keep him in that rotation and just manage the heck out of him -- make sure he is always starting if he is at 100 energy.
However, if some of those other starting pitchers are lower pitch count starting pitchers, I'd seriously think about using this guy as an LRA. This is especially true if the lower pitch count starters are LHP. Having a low pitch count starter LHP, then bringing in this guy as a great innings eating LRA would be awesome, but it would only work well if he came in after a low pitch count starter. Putting him at LRA with high pitch count starters would minimize his innings.