While the minor operation will rule Inglis out of the NRL blockbuster with Brisbane this week, Souths are hoping he will be fit to play against the Sydney Roosters in the final game of the home-and-away season.
"We've opted to go in there, get (the knee) cleaned out as quickly as we can and then rehab him and hopefully we'll get him back for the Roosters game," Thomson said.
Inglis' absence against the Broncos will be a blow as they try to keep their place in the top four.
Five-eighth Luke Keary admitted Souths would desperately miss Inglis.
"He's a big part of this side and he's our captain," Keary said.
"He's led us around all year and he's played really good footy all year so he's obviously important."
Alex Johnston is expected to move to fullback, having filled in there during Inglis' absence earlier this season.
Keary and hooker Issac Luke are to return from suspension in what has been an inconsistent season for the defending premiers.
After blowing North Queensland off the park in Townsville, Souths were badly out-muscled by the Bulldogs on Friday.
"That's the million dollar question," Keary said of his side's up-and-down form.
"We probably asked ourselves that over the last couple of months and we haven't come up with the right answer yet.
"We'll do it again this week and we'll see if we can turn it around."
-AAP
