"We feel for Lee because he's worked really hard and we wanted to get him a run of games," Saints boss Nigel Adkins told BBC Radio Solent.
"But we've got great medical staff here so hopefully he'll be able to make a full and speedy recovery."
The former Derby County player, who has made 10 first-team appearances for the Saints this season, landed awkwardly in the early stages of the match against Cheltenham.
"He had a big opportunity to show the potential and talent that he's got here but unfortunately, due to a freak incident, he's now going to be out for a considerable period of time and has had to have surgery," added Adkins.
Source: BBC Sport
Source: BBC Sport