Well he was recovering from a very serious injury. It's tough to come into a team late in the season, especially when the man you're competing against is going pretty well.
I know he was injured but a man of his class (and he was back long enough) should have been used more like he could've been the difference in the Amlin and I know that was to do with a non-european rule but if Toulon used brains they'd realize Contepomi should have been used as every team should have 2 quality 10's in 22.