Liverpool pair Yossi Benayoun and Albert Riera could be out for at least three weeks with hamstring injuries.
Both players limped out of Monday's Barclays Premier League draw against Birmingham at Anfield, adding to manager Rafael Benitez's injury concerns.
Daniel Agger and Glen Johnson also suffered injuries in the same game while the club continue to monitor key duo Steven Gerrard and Fernando Torres.
Manager Rafael Benitez said of Benayoun and Riera: "We will have to wait and see how they progress but hopefully in three weeks they could be available.
"We are disappointed because there are too many things at the moment that we can't change.
"Both players are wingers as well and for them to be out at the same time is bad news for us."
The Spaniard added on the club's website, www.liverpoolfc.tv: "Daniel Agger felt something in his back after the Birmingham game and didn't go with Denmark after we spoke with their doctor and manager.
"I think he could be back training again in a few days.
"Glen Johnson's was a strange situation because he finished the game on Monday and then travelled to London to be with England.
"He felt something in his hamstring and came back to us for a scan. Hopefully it's not too serious and he could be available again in a week."
Torres missed the game after beginning a rehabilitation programme on a niggling groin problem but Gerrard appeared as a substitute and scored the equalising goal in the 2-2 draw after overcoming his groin injury.
Benitez said: "With Fernando Torres we are talking about two or three weeks of treatment and working with the physios.
"I was talking with him this morning and he is doing well. Hopefully he can be running in a few days and we will see how he progresses.
"It was good to have Steven Gerrard back on Monday night. He is feeling okay and should be training fully with the other players we have here in a few days.
"Sometimes a break comes at a bad time because you don't like to see your players flying all over the world, but this time it gives us a chance to get some players back."
The international break will also give Liverpool some respite from a dreadful run of form, the Reds having won just one of their last nine games in all competitions.Reuse content