CARLTON is still sweating on the fitness of defensive duo Kade Simpson and Jacob Weitering, with both battling calf injuries ahead of Friday night's clash with St Kilda.

Fellow defender Caleb Marchbank is also being monitored for a raised heartbeat, while ruckman Andrew Phillips will miss the remainder of the year with a hamstring injury.

Simpson was a late withdrawal from the side's disappointing loss to Brisbane last week due to a tight calf, while Weitering sat out the final quarter with a similar issue.

The club remains hopeful both will pass fitness tests later this week.

"Kade's calf tightened up during the last session of the week prior to the Brisbane game," Carlton footy boss Andrew McKay said on Tuesday.

"We gave him every opportunity to play, but on Saturday morning we felt it was still too tight to risk playing him. He'll be a test at the end of the week and we're hopeful he'll be available.

"Jacob felt some tightness in his calf during the game. We were concerned about further injury, so he didn't see out the remainder of the game. He has pulled up well and will be tested at the end of the week."

Marchbank was discharged from a Brisbane hospital on Sunday, having had a raised heartbeat during the game, but has not yet been ruled out ahead of this week's match.

However, Phillips will miss the final seven matches of the season after he hurt his hamstring in the opening quarter of Carlton's heavy loss to Brisbane last Saturday.

"Andrew will see a specialist in the coming days to determine the full extent of the damage, but he will be sidelined for the remainder of the season," McKay said.

"Clearly we're disappointed for Andrew and this adds to our growing list of injuries, but we will fully support him in his rehab from this injury over the coming weeks."