Unfortunately for Sterling his dip in form came at the wrong time of the season. Pep has a history of playing players through the storm until they get better but Sterling's struggles came during the crunch part of the season with 4 competitions on the line.
Although Pep rotates a lot, he's begun to rotate more consistently at this stage of the season, with an almost precise starting and reserve XI established. As opposed to earlier in the season when it was more of a mish mash. For Sterling and the other reserves, it's only going to get increasingly difficult to build form when you're mostly playing with reserves.
Except for Cancelo vs Zinchenko, I'd say the first XI is set for the remainder of the season. What I'd say for Sterling as well as the others outside of this XI, is to do everything they can in training to ensure that when it finally clicks for them it clicks hard, and they really explode into life. Sterling (along with Laporte, Cancelo/Zinchenko, and maybe Jesus) are likely to get the odd game with the 1st team before the end of the season if we progress in the CL, as these would be the first choice reserves in the case of emergency or injury so they'd need to be ready. Sterling just needs to push himself. He has the ability.
One big possible thing that's harmed him this season is our increasingly slow play. You take Pep's fear of counter attacks, Aguero's fitness issues, and our lack of pace, and it's asking for a patient false 9 setup. We don't break teams down with sharp interplay as often, nor do we rely on fast transitions. It's more about meticulously carving openings and very precise execution, doing whatever it takes to not jump the gun early. We score more pullback goals where the furthest players forward occupy the centre backs near the goalline whilst another player (typically Foden or Gundogan) are on hand to tap in. There's far breaking the defence with Sterling scoring the open goal tap in.
One thing I'd say about Sterling is, he's come back from worse positions. In 16/17, 17/18, and 19/20, there were strong feelings that new signings (Nolito, Bernardo, Mahrez) would all see Sterling out of the team, and every time he dug in and made the role his own. Now he just needs to keep going.
And if he wants reassurance. John Stones was on the brink of being sold this summer, and if not for Garcia not renewing he may have been gone. Loads wanted Zinchenko gone after the Lyon defeat last year, all the way until our recent winning streak. Bernardo was actually being completely written off until that win streak. Gundogan was a player that from January 2018 up until the recent winning streak, very few thought was actually good enough. Rodri was a magnet for the doubters up until the winning streak. Torres was being written off before today. Even Mendy is getting credit. Every player in this City squad can pull through.
He struggled today, but he worked hard. That might not be enough for some, but that was what Bernardo was doing for over a year through his rough patch. It means that when it comes right, it really comes right.