Did anyone ever establish when he was injured or re-aggravated his injury last year? I'm not sure if it was ever posted, but it seems to look like it was the Detroit game the last week of the season? Not only was that the game that it appears his play turned down, he also had less ice time after that game, AND his stats turned at almost that exact moment:
Last year through that Detroit game (game #80): 79 games, 69 goals, 38 assists 107 points, +22 (72 goal, 39 assist per 82 pace).
Since then (including playoffs but not the 4 nations games: 45 games, 21 goals, 28 assists, 49 points, -1 (38 goal, 51 assist per 82 pace)