Yeah just read that, apparently never the same after his injuries.
Can only think Moyes has looked at Patterson and thought we can't be using him ever and so quickly needs a cheap option for a year until we can address the position properly.
One thing going for this kind of deal though is that Moyes knows how to get the best out of players, especially defenders so probably feels he can get Justin back to his best, and if not then JOB will cover the position instead.