Klopp spoke to reporters on Friday as he confirmed Keita would be missing due to a "fitness issue," but the Reds boss didn't comment on rumours of a positive test for coronavirus while on international duty.
Reports from a reliable Guinean publication last week claimed the 25-year-old was one of five players from the national team to test positive.
While further reports have claimed he has since tested negative - much like Xherdan Shaqiri with Switzerland - the club haven't confirmed the news either way.
"Naby will not be ready," Klopp said when asked about his current injury concerns.
The boss also provided an update on goalkeeper Alisson, claiming the Brazilian has made "big steps" during his rehabilitation from injury. However, he will remain on the sidelines against the Blues this weekend.
Klopp said: “[It’s] very, very positive with Ali, it looks really good. [He's] made big steps. I don’t have a timeframe, but it looks really good.
“That’s it, pretty much. Naby will not be ready. Apart from that, long-term of course, [Alex] Oxlade-Chamberlain is not and so on, but they all came back healthy from the internationals.”
Liverpool will have Thiago Alcantara, Sadio Mane and Joel Matip at their disposal after the trio returned to training this week, with Thiago and Mane both coming out of self-isolation earlier in the week.
On the duo, Klopp said: “We all learn on a daily basis about it. They are in training for five or six days [now].
“Then, of course, we assess that every day. We have our specific measurements, how we do it with heart rate and how we can measure if they are more fatigued than usual and stuff like this.
“They both looked really good, to be honest. We are very close with the doctors and we don’t want to – and would never – risk anybody.
“Usually in these cases, in at least the last three, four of five days of the quarantine, the boys are already ready.
"They cannot come out of quarantine, but they are on treadmills, on the bike and these kinds of things so when they start training again it is not that they start from nil. They have still a proper shape, so it should be fine.
“So many things are new at the moment and this is one of the things which is really new, but we try to be as sensible as possible.”
Meanwhile, skipper Jordan Henderson is set to return to the fold after making a comeback from injury for England during the break.
Klopp was also keen to reiterate his concerns about international football in the midst of a global pandemic as he highlighted the welfare of his players.
“I don’t like to answer this question because it always sounds like I am moaning about something that I cannot change,” Klopp said.
“What do you think about playing Wednesday night in Peru and then Saturday in Liverpool? Should it be like this?
“They all came back healthy, which is good. How fit? We’ve had one and a half days time to improve that and make them match ready. That’s how it is.
“First of all, I have to say both teams are in the same situation. Everton had players away and so did we, so that’s kind of fair.
“When it was decided this game was for 12.30pm on Saturday there was never a triple-header involved where the boys had to play three games in the same time where they usually play two. It’s already difficult enough to solve that.
“You can do it once but there should be no chance that the same teams have to do it twice.
“Now the challenge is always to make all the decisions with the knowledge we have in the second we make the decision and sometimes we have to overthink it again because something comes in between.”