There seems to be wrong information about Strootman.
He's had only 1 major injury, he tore his ACL which got reconstructed. He came back, started training ahead of schedule and even got some minutes on the pitch. He then felt something wasn't right, he didn't play after this and had a (don't know the correct translation, sorry!) look-operation? They found that nothing was wrong and that the reconstruction of his ACL succeeded, but in the same operation they also removed some scar tissue to make it easier for him in the long run. This means he's out untill pre-season, but there were no major complications.
He's on his way back and I doubt van Gaal has fully given up on him. Wether we're going to buy him? Not sure, I wouldn't put my money on it. He is exactly the type of player (pre-injury) van Gaal still wants to add to the selection. Currently we have no backup for Fellaini, someone who brings defensive balance. Strootman is that kind of player.