The Saints’ key ruckman underwent arthroscopic surgery to remove loose cartilage in his right knee on Monday morning.
“The arthroscopic surgery went well,” said Saints Medical Officer Tim Barbour.
“I saw him yesterday and things are going fine. It’s now just a matter of the swelling going down and getting strength back.”
McEvoy injured his knee late last week at training, forcing him out of St Kilda’s match against Hawthorn on Saturday night.
“There was no single incident that occurred, he just pulled up sore late last week,” said Dr Barbour.
Senior Coach Scott Watters said the results are extremely positive for the Saints, with McEvoy expected to return to training ahead of Round 12.
“We’re looking at a 4-6 week spell for Big Benny,” said Watters.
“That presents a really big challenge for Rhys Stanley and Kosi. We also saw the work Jason Blake did last week, so we really need to shoulder the load in that area.”
The 22-year-old has played 58 career games, all for the Saints.