Wataru Endo wasn't involved with the Liverpool squad in the lead-up to their clash with Manchester United but was spotted training by himself.
The Japan captain was left out of his nation's friendlies against Paraguay and Brazil earlier this month after suffering a hamstring injury during his four-minute cameo in the Reds' 2-1 defeat to Chelsea two weeks ago.
Endo, 32, remained at the AXA Training Centre for treatment throughout the international break in a bid to return to full fitness ahead of the return of club competition. With Liverpool hoping to end its three-match losing streak against the Red Devils on Sunday, it remains to be seen whether the defensive midfielder will be available for the clash.
Spotted by cameras in an individual training session on Friday, his absence from the squad means it may be a tall order for Endo to be part of the matchday squad, leaving Arne Slot without his sole cover for Ryan Gravenberch.
The Dutchman did not provide an update on Endo's journey to full fitness in his pre-match press conference but his reverence for the midfielder is well-known. It was earlier this year when Slot showered praise onto Endo for his superb attitude and versatility.
He said of the Japanese ace: "Wherever you play him, Wata is like, ‘Yeah, I’ll do my best, whenever you play me.’ So, if it’s five minutes before the end, he comes in and gives everything he has," Slot said earlier this year.
"That might be normal for a lot of fans to hear, but for as long as I’ve been in football I’ve seen players who’ve had to come in five minutes before the end also doing different things and showing different energy than Wata shows. He is an important part of our team. Every time we need him, in the midfield or even now as a centre-back."
A key rotation player for Slot, Endo embraced the reputation of being a 'closer' last season given his introduction on the pitch usually came in the latter stages of a game where the Reds were winning with Endo entrusted to keep the lead for the team.
"People started calling me a ‘closer’, but I don’t think people would call me that if I’d come on in the last 10 or 15 minutes of a game and conceded goals every time," Endo said in the summer. "The ‘closer’ position is one I finally won in the situation I was placed in.
"I’ve been called a ‘closer’ as a result of fulfilling the role I was given, so it means that I’ve found my purpose this season. I think there’s a high possibility that I’ll be able to play in various positions in the future, so I think I can carry that over to the next stage."
He's found game-time hard to come by this season, however, having played just 36 minutes of football in the Premier League with just six minutes of play in his last six league games.