He's in Wild shape and not Sabres shape.
He is getting more ice time than he did over the last 10-20 games in Minnesota and the pace is different.
I don’t think he has had the cardio all year with the injury stuff. He will need more than just games to get up to game speed. He also likely isn’t practiced at the short area stuff Don and his staff use, so there will need to be adjustments to his processing speed for what his teammates are doing.