Daniel Agger
Agger a doubt for Saturday after freak gym accident. (Reuters)

Liverpool are waiting to learn the extent of an injury Daniel Agger suffered during a freak gym accident in the build-up to Monday's draw with Swansea City.

The Denmark international missed the game at the Liberty Stadium after hurting himself as he attempted to jump out of the way of a falling weight at the club's gym facilities, the Daily Mail report.

Deadline day signing Mamadou Sakho was called in to replace Agger for the clash against Brendan Rodgers' former side and may retain his place after the Liverpool boss revealed the club are uncertain if the Dane will have recovered in time for the visit of Southampton this weekend.

"As for Daniel, it's too early to say whether he will be fit for Saturday," Rodgers said. "He had a freak incident in the gym.

"Just before he was coming out to train, he overstretched trying to prevent a dumbbell falling on his foot.

"He has overstretched and yanked his side. We are waiting to see if that settles down over the new few days. If it doesn't, we have got ample replacements. That is why we brought in extra players."

There was also concern for Brazilian midfielder Coutinho who was immediately substituted with a shoulder injury after being on the receiving end of a robust challenge from Swans skipper Ashley Williams.

Rodgers confirmed that the former Inter Milan starlet will have a scan this week in order to assess his fitness.

Both Sakho and Chelsea loanee Victor Moses made their Liverpool debuts last night as the club returned to the summit of the Premier League.

Although slightly at fault for Joinjo Shelvey's opener after just two minutes, the Frenchman enjoyed some impressive moments throughout the game as did Moses, who struck Liverpool's second.

"Sakho did very well," Rodgers continued. "He has played a lot over pre-season but he has come back in and done very well. I thought he was excellent and assured. Once he gets used to working with us, he will improve.

"I had a felling (about playing) Victor coming here. When I was manager here, he always played well against us. Her scored here and also scored for Chelsea here. I just had a feeling about him and his goal was very good.

"He is still getting up to speed. These boys who haven't played a great deal over pre-season but overall, we had moments that were very good. We had fluency and quality. When Coutinho went off, we probably lost that connection between our midfield and forwards."