Liverpool boss Jurgen Klopp has called on the footballing authorities to quickly make a decision over defender Joel Matip's eligibility after being forced to leave him out for the meeting with Manchester United.
The Reds released a statement two hours before the match was scheduled to get underway announcing that the 25-year-old had been pulled from the squad over concerns about his availability.
Matip, who had recovered from injury in time to play a part at Old Trafford, was called up to Cameroon's Africa Cup of Nations squad but declined the invite to take part in the ongoing competition.
Liverpool feared a potential points deduction if it later turned out that the centre-back had not been given the green light to play by FIFA, which Klopp is hoping will be sorted prior to Wednesday's FA Cup third-round tie with Plymouth Argyle.
"Our understanding is Joel is retired from international football - and we, the club, did everything we had to do to make this clear but until now we could not get the response we need to be 100 per cent sure that he can play," he told reporters. "It's pretty difficult and pretty frustrating, to be honest.
"He's been in training for five days and would have been in the squad, 100 per cent, maybe on the pitch today, so I don't think it's fair. But we cannot do more and are still waiting on the decision. We could not take the risk, but we need to get an answer as quickly as possible because on Wednesday we have the next game and then another game and another game.
"We cannot wait forever. It is public now, we have this problem and we are not the only team with this problem. I think Tony Pulis said a few things about it so I don't think that it is fair for the fans, for the clubs, for the teammates and for everything. Now we have to wait in this moment and think about the game – and then after the game we will try again to get answers."
Matip has featured 12 times for Liverpool in the Premier League since joining from Schalke 04 in the summer.
