Liverpool defender Nathaniel Clyne has been ruled out for "a significant period of time" as he continues to recover from a back injury.

Clyne, 26, has not featured for the Reds this season having missed almost the entire pre-season campaign. The former Crystal Palace and Southampton defender was a notable omission from the club's Champions League squad which was announced on Monday, sparking fears the club's first-choice right-back faces a lengthy spell on the sidelines.

Clyne is continuing to undergo rehabilitation at the club's facilities at Melwood but manager Jurgen Klopp does not expect the England international to be fit for the duration of the Champions League group campaign, which could see him ruled out until December.

"Nathaniel is working hard on his rehab and we have kept a close eye on his progress, but the reality is we are looking at some time still before he is back and available for selection," Klopp told the club's official website. "I am told it will be longer than just a couple of weeks, so we will continue to monitor and assess.

"It is pretty certain he'll not be available for the majority of the Champions League group matches. If we are fortunate enough to still be in UEFA competition in the New Year he could be added to the squad then. The medical guys are pleased with how he is responding and Nathaniel has shown a really strong attitude, given he is not someone who is used to being out injured."

Liverpool are able to register Clyne for the knock-out stages of the competition in the New Year – providing they qualify from their group.

Without the club's first-choice option, Klopp will be looking towards teenage duo Trent Alexander-Arnold and Joe Gomes to fill the void on the right-hand side of his defence.

"What is positive for us is how Joe [Gomez] and Trent [Alexander-Arnold] have stepped up and grasped their opportunities," he added.

Clyne will join Adam Lallana in the treatment room, with the midfielder still sidelined after a thigh injury.

Nathaniel Clyne
Clyne was left out of the club's Champions League squad for the group phase of the competition. Getty Images