Collingwood could be forced to take a depleted midfield into the AFL home-and-away season after losing Steele Sidebottom to a calf issue during their six-point loss to Richmond.
Sidebottom went off the ground during the first quarter of the pre-season match at Marvel Stadium on Friday night.
He returned briefly, but was ruled out with what the club later described as "calf tightness".
The 30-year-old joins fellow vice-captain Taylor Adams (hamstring) in a race against time to be fit for the round-one showdown with the Western Bulldogs at the MCG on March 19.
The midfield injury issues come after the Magpies forced out Adam Treloar during last year's trade period, and with Jordan De Goey set to spend more time in the engine room this season.
Adding to Collingwood's injury woes, unlucky youngster Will Kelly broke his left collarbone during the 11.14 (80) to 11.8 (74) defeat to Richmond.
The 20-year-old father-son selection, who dislocated his left elbow on debut last year, was hurt in a marking contest with Dylan Grimes and faces another lengthy stint on the sidelines after being taken to hospital for surgery.
"Will Kelly just can't catch a break," Collingwood coach Nathan Buckley said.
"It was a really clean hit and snapped it.
"Steele was a tight calf and it was almost bilateral, so it's a strange one, but we'll see how that settles down over the next couple of days."
De Goey, who hurt his left knee in a straightforward knee-on-knee clash, was one of Collingwood's best in a predominantly midfield role against the Tigers.
He played out the match and had 27 disposals, five clearances and two goals in a game that both coaches noted was low on pressure.
They put it down to the new rule prohibiting movement from players on the mark, coupled with player fatigue on return to standard-length quarters.
Jeremy Howe was strong again in defence on return from last year's knee injury while key forward Mason Cox kicked three goals when he came alive for the Pies after half-time.
But Richmond led by a comfortable 21 points at the main break and were able to hold off Collingwood's challenge.
Jayden Short (43), Jack Graham and Josh Caddy (27 each) racked up plenty of touches and Dustin Martin showed flashes of his best, starting with the first centre clearance - one of his four for the night.
Jason Castagna kicked four goals for the Tigers.
"Overall I was pleased," Richmond coach Damien Hardwick said.
"Defensively we were very solid and offensively we moved the ball pretty well."
Australian Associated Press