Walker, for all his Celtic pride, never got the most out of his ability, and in part due to his own failure to keep in prime shape, he's washed up at the age of 31. That's a shame. I liked Antoine when he was here, but he could have been a much, much better player than he turned into.
If he worked on his game and his conditioning in the off-season like so many coaches implored him to, he'd have more than a 3 inch vertical leap right now. He's one of the best passing and offensive rebounding forwards to come into the league in a long time, and all he did was brick perimeter shots. Again, a pity.