On a team with Nyquist, Tatar, Franzen, Jurco, the emergence of Abby, at least one of Zetterberg/Datsyuk/Weiss playing the wing and then Pulkkinen and Mantha sitting in Grand Rapids, trading for Perron or Eberle is a waste of assets, as talented as they are.
Petry is a fine enough defenseman, but he isn't really an upgrade over Dekeyser, Ericsson, and probably even Quincey at this point (a compliment to Quincey, not a knock on Petry), and Detroit would have to ship off an NHL defenseman anyway if they were going to add one.
And Schultz, while he would be intriguing, I'd be concerned that he'd flounder under a coach like Babcock.
But most importantly, if Edmonton needs centers, look elsewhere. We have 3 types of centers: the ones we won't trade (Datsyuk, Zetterberg), the ones we can't trade for the sake of our future and our lack of prospect depth down the middle (Sheahan, Larkin), and the ones you don't want (Weiss, Andersson, Glendening, Ferraro, etc.)