Not sure why would you bring up that he might not be able to play against tougher teams. He's a 6'3, 220lbs power forward, who can skate fairly well. Besides that 1 year, where he missed almost the entire season, he's been rather durable (missed 40 or so games in 7 season playing in the West, since his rookie year).
Saying that he's not a playoff performer based on his last 3 postseason is like saying Datsyuk or Claude Lemieux isn't a playoff performer.