As with most athletes, confidence is a major factor. I've watched Freddy play for a while now, and I don't think it's as much workload, as it is confidence. Sure, workload can wear you down, when he's receiving the most shots in the league. But with the team playing more of a run and gun style, the amount of goals against will dig away at your confidence.
I hope the leafs go out and get a player or two, to help team d and the blueline. I'm sure Freddy will get back to playing better, it however still wont be enough to go deep in the playoffs if this teams blueline and team d (and goaltending) doesnt improve.