If you google it, there's media reports of him being ready to return from injury in March, June, September, and November of last year, and this is at least his second problem with us. It might not be the case that he's physically weak in particular incidents, but whether it's caused by lifestyle, or attitude to preparing for games, or just some unfortunate position he finds himself in, he doesn't tend to last for long before some part or another breaks.
The guy is and always will be injury prone, if he`d stayed fit since moving to man utd then he would have made many more appearances then he actually has. Some players sadly despite their apparent skill levels are made of glass, he is one of them. I`m guessing Brucie was hoping he could stay fit for three months, and if he had perhaps he may have made a difference, alas it isn`t to be. The true crime will be to buy him, knowing how fallible he is to injury.