The midfielder was named in the starting line-up for the encounter with the Blades, but suffered a groin problem while preparing for kick-off in the pre-match warm-up and was replaced by James Milner in the XI.
Keita will now undergo further assessment with the club’s medical team to determine the severity of the issue, but Klopp has ruled him out of Sunday’s FA Cup third-round fixture with the Blues.
The manager said: “I don’t know exactly what he has – it was the groin – but I can say already he will not be involved against Everton.
“That makes it 12 adult players we have [available], plus the kids, so that’s not cool, but we cannot change it.
“I have no clue how it happened, I think it was the last shot in the warm-up when he felt something. He came in [the dressing room] and was limping.
“Everybody who has played football has had this kind of injury and it’s not nice, it’s painful. I don’t know exactly what it is or how long it will take, but I can say already he will not be ready for Sunday.”