Will Hoskin-Elliott will undergo minor leg surgery on Monday, with Collingwood football boss Geoff Walsh unsure when the forward will be ready to play.
Hoskin-Elliott had dealt with a problem in the iliotibial band in one of his legs for some time and it "gradually got sorer", according to Walsh.
The iliotibial band is a long tendon that runs down the outside of the thigh, crossing both the hip and knee joints.
Essendon goalsneak Orazio Fantasia had a similar problem last year and was back playing one month after the operation.
A similar period on the sidelines would rule Hoskin-Elliott out of the Magpies' JLT Community Series matches against Fremantle (March 4) and Carlton (March 11).
Collingwood starts the premiership season on Friday, March 22 against Geelong under lights at the MCG.
"He'll be off legs for about seven to 10 days then we'll just see how he goes from there," Walsh told AFL.com.au of Hoskin-Elliott.
"I wouldn't be putting any timeframe on it, because it's something we'll treat systematically as he returns to being able to run and that sort of stuff.
"It's pretty common."
The news comes just two days after Jordan De Goey sent a scare through the Magpie camp when he landed awkwardly in a marking contest in match simulation.
He has since been cleared of major damage and diagnosed with a mid-foot sprain in his left foot.
Other key Collingwood footballers are also in a race to regain full fitness as the season approaches.
Brodie Grundy (toe) remains a chance to play in the Pies' practice match with Melbourne on February 22 and Lynden Dunn (knee) is aiming to play somewhere by round one.
Jeremy Howe (corked thigh) also had further surgery a fortnight ago after a knock at training aggravated an issue that saw him miss four games late last season.