Beginning to lose a lot of patience with him now. He has had some serious injuries during his time here but he also seems to be regularly sidelined due to "niggles". As people have mentioned in here, sometimes you've got to play through the pain barrier. Especially if you're in his position.
He must be aware that he's yet to fully prove himself at the club, and if that was me I certainly wouldn't be letting a "niggle" stop me from doing that. Play through the pain barrier and prove your worth. The likes of Salah & Henderson have played through injuries this season, Van Dijk through illness. That's what winners do, and they're some of the first names on the teamsheet, they could easily sit out a game or two and end up straight back in the team when they feel they're ready again. Keita isn't even a key player like those three are, he should be pulling out all of the stops to get himself on the pitch in my opinion