This makes no sense for either team. The Pen's game is built on speed. Why would they take speed out of their line up? Add to that they'd be adding more salary to their cap, it would be a bad choice on their part.
Perry is a good player, but for the most part, doesn't really add anything to the Pens that Kessel doesn't already have in terms of scoring.
As for being a winger for Crosby, there's no guarantee that will work out. Why mess with a line up that just won you the cup? The Pens have three players, Crosby, Malkin, and Kessel, that each drive their own line. That was one of the keys that won them the Cup. Why remove that key element now?