The Brazilian was replaced by Iago Aspas after 55 minutes at the Liberty Stadium after falling awkwardly following a challenge from Swansea skipper Ashley Williams.
The 21-year-old was seen leaving the stadium with his arm in a sling and after the game and Liverpool manager Brendan Rodgers had revealed Coutinho "was very sore in the changing room."
On Monday, Rodgers said he hoped Coutinho's injury was nothing more than bruising but it is now clear the injury was worse than originally feared.
Following an assessment of the injury by Liverpool's medical staff it has been decided that Coutinho will now have surgical stabilisation on the AC joint in his shoulder.
The injury will stretch the Liverpool squad even further after a recent spate of injuries.
Daniel Agger sustained a rib injury forcing him to miss the game at Swansea and defensive partner Kolo Toure has only just returned to action following a groin problem.
Fellow defenders Glen Johnson, Aly Cissokho and Sebastian Coates are all out injured for Liverpool, while midfielder Joe Allen is currently sidelined and Daniel Sturridge has only just come back from a thigh injury.