St Kilda have made an “extremely late” change with young gun Matteas Phillipou forced out of the blockbuster against Collingwood on Saturday night.

Phillipou injured his calf during the warm-up and was withdrawn minutes before the opening bounce.

The 20-year-old was shattered on the bench when he spoke to coaching staff.

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“It’s unfortunate, you can see how distraught Phillipou is,” commentator Jason Dunstall said.

“He’s had a horror run with injuries and just wants to get in there ... he’s going to be the latest of outs.”

The club confirmed it was a calf issue with Ryan Byrnes coming off the emergency list into the starting 22. Tobie Travaglia remained as the substitute.

“He’s been managing a plantaris issue since the Melbourne game, he trained fully all week, had no problems,” GM of football David Misson told Fox Footy at quarter-time.

“First warm-up, no worries. As soon as he came out for that second warm-up, he felt a sharp pain and said he couldn’t play.”

Phillipou was later seen in the rooms left to rue another injury.

“Our sports science (department) were a bit concerned he could do a soft-tissue injury under a full game,” Saints coach Ross Lyon said in his post-match press conference.

“And he was going to play and we were (going to play him a full game).

“He was in the warm-up ... so it was like we’ll keep him. Everything’s smooth and then I got a call from Dave Misson (saying) ‘Mattias is sore in that part of this leg’.

“Not dramatically but he was pretty upset with it all and we said no worries, no problem. I got on the phone, I said ‘mate don’t worry about it, you’re fine, we love you, don’t get too upset, let’s get you right’.

“He’ll be upset, I’ll get to him and we’ll work our way through it.”

Phillipou was tipped for big things heading into his third season in the AFL after a big finish in 2024.

But his year was derailed by a stress fracture during the pre-season.

He finally returned in Round 9, playing three games before he was struck down by a plantaris issue early against Melbourne in Round 13.

Phillipou missed last week’s loss to the Western Bulldogs, but was set to return this week before the dramatic late blow.