Just don't see it (right now).
I wouldn't exactly say he was "so good" last year. Julio was barely making it to the 5th inning let alone 6th inning last year. He was not all to efficient with his pitch counts and a good portion of that is overthrowing and trying to blow past hitters. I remember several games at the top of my head where he was already around 80 pitches by the 4th inning. We all know Fredi's max is 100 for anyone not named Hudson. If Julio was in the 5th with runners on and around 88-90 pitches, Fredi would go to the pen asap.
It was a learning experience for him for sure because he realized it wasn't hte minors anymore and he couldn't just rely on stuff. Wood on the other hand was way more impressive with his command and pitch selection. He was much better at attacking hitters, and I think Fredi would have let him pitch deeper into games had he been stretched out the entire year and not in the bullpen.
My worry with Julio is does he have the smarts to figure out how to pitch to contact and get quick outs, as opposed to trying to plow through hitters.