A few under Koeman, then change.
A few under Unsworth, then change. (...and he looked one of our better players at the time though)
Then Allardyce came in and NO ONE looked good under him, we bypassed playing on the floor and couldn't keep the ball for 5 seconds.
40 minutes under Silva.
All the while this was trying to accommodate Rooney in the same team. He could turn out to be a flop but don't say he has had a fair crack of the whip yet, because he hasn't.
While there are certainly factors that he wasn't to blame for when he first came in, I also won't excuse Gylfi for being utter tosh for the first 10 games or so. He was awful, like the rest were, and he evidently wasn't sharp.
But once he got played in that 4-3-3, as the left sided forward, it started to click. Rooney a bit deeper getting on the ball and Gylfi provided a good link up option. The few times we played that system (with Gana as the lone defensive midfielder and Davies in a box-to-box role) we actually looked okay.
Once Gylfi got injured we saw Rooney's form drop even more as he was getting on the ball with no options (coming to the ball) ahead of him.
Tosun would try to link the play and then Walcott would run in behind, but neither of them had the ability to get on the ball, turn and pass/shoot/cross that Gyfli has.
As it stands, I'm not sure he gets in our strongest team when all of the others are fit, but it depends how Silva wants to set up. And slating the lad for Saturday is ludicrous. First game of the season, he had to make way because of the red card and during his time on the pitch we were reverting to going long anyway because Schneiderlin / Gueye were offering no options to pass out from the back (Schneiderlin to blame here more than Gueye, imo).
So yes, he could have played better, but he didn't really play badly.