COLLINGWOOD midfielder Scott Pendlebury is in danger of missing the rest of the finals if scans on Monday confirm a suspected broken leg.

To further compound the Magpies' injury concerns, veteran Anthony Rocca faces a race against time to play next Saturday night against Adelaide, after rolling his "bad" ankle late in Sunday's qualifying final at the MCG.

Pendlebury, 21, was tackled by St Kilda's Leigh Montagna in the opening minute of the loss to the Saints, with his leg buckling beneath him.

He was helped from the ground, but returned to the field later in the quarter. He gingerly ran out the first half before conceding at half time, and then watched the rest of the game from the interchange bench.

Coach Mick Malthouse said it appeared Pendlebury had fractured his fibula, and not suffered a reoccurrence of the knee injury he sustained in round 12 against the Sydney Swans.

"You don't reinjure perhaps a broken leg," he quipped, when asked if the young gun had inflamed the previous complaint.

"We'll lose Pendlebury from what we can gather, and Anthony would be under pressure given he's hurt the same ankle that's he's had operated on.

"How he comes back from that will depend on whether he plays."

Rocca was playing in his first senior game since round seven and just his fourth for the year after a season ruined by persistent problems with the ankle.

Malthouse said it was hard to evaluate his two-goal performance, given the Magpies' lack of midfield drive.

"He was limited with opportunities. We got the ball in there 30-odd times, and until the last quarter it was 21 or 22. It's very hard to be a marking forward if the ball doesn't go in there," he said.

In the rooms after the game, Rocca's left ankle was noticeably swollen.

Malthouse agreed the Magpies could look to the reserves for replacements given the strong performance of the VFL side in Saturday's elimination final win over the Casey Scorpions.

However, he said they wouldn't be making any knee-jerk reactions against players who failed to fire against the Saints if they had shown solid form in previous rounds.