As much as I like the big man's style of play I really do think this might be the end for him at this club, at least as a starter. And this has nothing to do with his potential long-term injury.
At first I was thinking that his recent poor performances might be because of fatigue, but now I really do think it might be the easiest answer, age. Even he has to face what all other players do, age has unfortunately caught up with him. He still has a lot of good things in his play, but makes more mistakes than usual. And the 'killer-instinct' doesn't seem to be as strong as before.
I do hope I'm wrong and that he'll prove me wrong, which he's done many times before when I've thought the exact same thing. But even if this might be the case, he's at least proved many doubters that they were wrong when they assumed that Ibrahimovic wasn't good enough. Despite playing as a 35 year old in his first season in the PL he has still been among the best and we can only imagine how good he would have been in the PL 5-10 years ago.
I'd actually still like him to stay next season even if he is starting to decline, but I would of course want him to be a back-up for whoever is going to be the starting striker. But I doubt that he would be interested in something like this, since he'll likely find many clubs that are going to want him as a starter.
If this is his only season I'm still grateful for his contribution. He's been a true professional and even exceeded my expectations for his first season. Now I just hope that his injury isn't that serious and that he can continue to play this season, hopefully in the Europa League Final which is in his home country. And then we will see what the future holds.