The striker scored his second Premier League goal for the Reds at Tottenham before injury struck
Alexander Isak could be set to miss the huge showdown between Liverpool and his former club Newcastle United in January, after being forced off in their 2-1 win over Tottenham Hotspur on Saturday evening.
The Swede scored only his second Premier League goal for Arne Slot's side since his acrimoneous £130m transfer in the summer, after coming off the bench at half-time against a Spurs side who had already had Xavi Simons sent off.
Isak broke the deadline on 56 minutes after a pass from Florian Wirtz to take his tally to three for Liverpool in all competitions.
However, his joy did not last long, with the striker hobblig off soon afterwards, casting doubt over his participation in coming games.
Newcastle go to Anfield on January 31, looking for some revenge following the cruel 3-2 St James' Park defeat to Slot's side in August, and much of the focus in the build-up will no doubt be on Isak's form and fitness.
Slot was unable to offer any definitive timescale for his return, but admitted it did not look good at this stage.
"I don't have any news," Slot explained on Saturday night.
"But if a player doesn't even try to come back, that is usually not a good thing but I cannot say anything more than that. That is just gut feeling and nothing medical.
"The goal is what we would like to see happening a lot. A good finish, a good pass, but let's not be too negative yet. We don't know yet. Let's hope he is back with us soon.
"With Alex and Conor Bradley we have to wait. You could see our bench as well, but this is not the first time in the last few weeks and we're picking up points. That's the main thing."
Spurs also had Cristian Romero sent off late in the game as they suffered a 2-1 home defeat, with Liverpool now showing more consistent form.
Slot added: "Of course we're happy with that but when we started the season, it wasn't as if I was thrilled and completely happy when we were top-four.
"We're always aiming for the best possible and after the very good start we had, we were disappointed with the run of results we had afterwards, but we are now on equal points for top-four.
"I think it has never been as bad as people said, but it's also true that we are definitely not perfect yet. We knew this and when we made so many changes in the summer, that it would take time."
Tottenham are seven points off Liverpool and will be without Xavi Simons for three matches after his first-half red card.
Captain Cristian Romero will also sit out the trip to Crystal Palace on December 28 following his sending-off, but Frank vented his frustration at Xavi's punishment after his tackle on Virgil van Dijk.
"Yeah, that's of course disappointing," Frank reflected. "If it was intentional or a very stupid tackle, which I don't think it is, then it's one thing.
"So, I just think it's too harsh a tackle like that can be three games.
"One game? OK, that's one thing, but three games? Of course, is too much."
Xavi added: "Mistakes happen. Virg is my captain, I would never intentionally hurt him or anyone. To my Spurs team-mates, my manager and the fans, I take responsibility. I'm really sorry."