We most certainly need a win on Saturday and, yes, I believe our chances of that happening are improved with Alexis on the pitch, but I would STILL have him on the bench. I think it is very short-sighted to disregard what is clear for all to see; during our last 2 games Alexis has been less effective, and he has looked leggy and shown signs of fatigue.
We can all bemoan our lack of depth/quality in certain positions, but our manager needs to learn how to use the squad he has in a smarter way. As Klaus pointed out with Wilshere, the manager played him way too much the season when he had his big injury, and that injury was absolutely down to that. Koscielny's injury is ALSO down to overuse. Tendinitis on BOTH of his Achilles tendons, and yet he played EVERY game until he invariably broke down. I think it is fair to say that we would have missed him in any of the games where he should have been rested throughout last season and the beginning of this season, but we have suffered waaaaay worse by having him out for this long. Wenger is doing the same with Mertesacker right now, he did it last season with Ramsey, Giroud, Sagna and Özil. I don't think it is a coincidence that Welbeck is out now too, but maybe he was just actually rested for Dortmund. I hope that is the case at least.
Sanchez NEEDS a rest NOW, and Gibbs, with his history of muscle injuries, should NOT be played every game. That is my view anyway.