Given that you recruited him, I wouldn't take the risk of cutting him. The odds of having another guy leave are higher than some people realize. Yeah, he's never going to be a great player, or even a good one. But he won't be bad enough that he's worth cutting at the risk of losing someone you're planning to build around...
This is exhibit A for why most coaches would rather take a walk-on over a guy who'll never develop into a great player. Presumably he started with some very poor highs, in athleticism and at least one or two other things? Bad gamble, basically. But I think you just have to live with that and ride out the career, you can easily find a guy like that 8-10 minutes off the bench to shoot a few 3s and grab a few boards.