We have seen (and will especially see again over this period of multiple matches within a short space of time) Klopp & the medical team clearly monitoring EVERY player and limiting their minutes based on the results of that monitoring - this is nothing but common sense.
That doesn't however infer that any of the players are not fully fit (note I didn't say not fatigued). Klopp / Medical Team seem to drop them back into recovery mode at any hint of an injury. So I sincerely doubt, though I could easily be wrong of course I'm just guessing like any of us, that Keita is anything but fully fit, he is not however match fit so there is only one way to attain that 😉