He only returned to training earlier this week, having earlier spoken about the New Year's Eve showdown with Manchester City as a potential comeback date.
And after such a long time out, Klopp has declared that the 24-year-old won't be at peak fitness for the meeting with bitter rivals United at Old Trafford - although he will get at least some minutes.
Coutinho is expected to make his comeback in the Reds' EFL Cup semi-final first leg away at Southampton on Wednesday night, which should allow Klopp to gauge how sharp the playmaker is.
We will do "everything" to get Coutinho close to full fitness for United, vows Klopp
The Reds boss told reporters that "the time is not long enough" for Coutinho to be fully fit for United, but said "he could play" and that they "have spoken before about there being a difference between being fit and match fit."
Klopp added: "But of course, it's Phil, so we want to try everything we can to bring him as close as possible to his 100 per-cent. In this moment, I would say it makes sense for him to be involved against Southampton in the squad, and we will see what happens there."
The German said that he would see "whether we have to use him or not or whatever" at St Mary's Stadium dependent on the game, insisting that if he isn't used then they "have another three days to prepare him" for the clash with Jose Mourinho's United.
He stated that "a few minutes for him does make sense" at Southampton, insisting they will keep a close eye on whether he is "ready" throughout the day on Wednesday.
"No plans" for Coutinho to leave Liverpool
Coutinho has missed nine games through injury and though they won five - including huge wins over Everton and Manchester City - Liverpool's levels of performance have not been as scintillating as they were with the diminutive No.10 in the team.
Such was his influence earlier in the campaign, plundering six goals and five assists in 14 appearances in all competitions, Klopp insisted that the club aren't willing to entertain interest from the likes of Barcelona and Paris Saint-Germain.
With the manager asked whether Coutinho's spell on the sidelines might allow interest in his talents to cool, he said: "It would be nice if big clubs thought like this and forgot about a player completely because he's been injured for five or six weeks. I'm not sure it's like this."
Klopp added that Liverpool have "never had any ideas or plans or any talks" about Coutinho leaving the club, and said that "nothing [has] changed" in their situation.
He said that interested clubs "don't think this way unfortunately" and said that there is "no question of him not being the same player afterwards" because he did not suffer from "a big injury."