Ralph Hasenhuttl's side are in the market for a creative midfielder this summer and former Southampton player Lallana is one of the few names being considered.
Lallana, who was Saints captain during his eight-year spell at the club, joined Liverpool under Brendan Rodgers in 2014.
The 30-year-old has put in some excellent displays during his time at Anfield, however injuries seem to have taken their toll on the England international.
Lallana has made just 16 appearances in all competitions for Liverpool after suffering from various niggles and injuries throughout the season.
He has not featured in Liverpool's last seven games after initially missing out with a slight muscle strain, with his last appearance coming against Fulham in March.
Reds boss Jurgen Klopp named his 23-man squad for the trip to Barcelona on Wednesday night and Lallana was the biggest omission from the squad having not been involved in training for the past few weeks.
He has a little over a year left on his current contract with Liverpool and is not expected to sign a contract extension.
Klopp will be looking to add to his squad this summer and Lallana could be deemed to be surplus to requirements owing to his age and constant injury problems.
Lallana left St. Mary's under difficult circumstances with Saints supporters infuriated with their captain for making the move up north.
Southampton legend Francis Benali says he would be open to the idea of the club re-sigining Lallana, saying: “It's a difficult situation for him to get back in the team.
“It's a scenario that many players would find difficult. But what would be the tough thing is would the supporters welcome players [like Lallana] back to the club?
“It's a relationship between the two clubs that has certainly spiked the nerves of Southampton fans with a lot of our top players leaving for Liverpool.
“I just like to see good, talented and passionate players that want to play for Southampton - playing for my team. However that happens, I'm quite open to anything.”