It seemed to me late last year and earlier this year, Perk had a decent 1 on 1 offensive game going. He had improved on his foot work and his turn around jumper in the paint. Add that with his hook shot, he had a decent 2 pet moves to go to down on the low block.
I dunno if it is his knee injury or his shoulder or what have you, but something has caused Perk to lose his footwork and make his move too quick which causes those unnecessary traveling violations.
Or it could even be mental thing. I've heard Doc talk about Perk being down on himself for failed offensive opportunities (i.e. slumped shoulders, head down etc.); this mentality could also drive Perk to do things out of his own element = making his post moves quicker resulting in travels.
For 50 games this past regular season, Perk was the 2nd best Center on a contending team. (And the most improved from last season; Dwight Howard actually regressed this past season).