COLLINGWOOD is "very concerned" about Ben Sinclair's fourth concussion of the season, with the Pies deciding not to rush the defender back onto the field anytime soon.

Sinclair was involved in a heavy collision with North Melbourne's Jed Anderson on Friday night and was taken to hospital after the game as a precaution.

That follows head knocks against Melbourne (round four), West Coast (round six) and at training ahead of the Pies' clash against Geelong in round nine.

Magpies coach Nathan Buckley was unable to put an exact timeframe on Sinclair's return, but said the backman would not be risked against West Coast this Saturday.

"He may (play again this year) – he won't play this week," Buckley told Fox Footy on Monday night.

"He may pass the tests that are prescribed but he won't play this week as a precaution and then we'll judge it down the track."

Earlier, Magpies football boss Neil Balme said Sinclair was in good spirits at training on Monday, adding the club would take every precaution in the 24-year-old's road to recovery. 

"He was at training today and he's actually going quite well," Balme told collingwoodfc.com.au.

"Obviously we're very concerned about the whole concussion thing.

"He's now had three or four this year. It's not an easy thing to overcome."

Sinclair told AFL.com.au earlier this month that he was sent to see a neuropsychologist after experiencing dizziness, nausea and even blurred vision following his concussions.

He has played 63 games in seven injury-plagued seasons at the Magpies and had just started to find his groove in recent weeks, racking up 23 disposals and five clearances against Adelaide in round 17.

"We'll miss him as a player. He's been very important to us," Balme said.

"Obviously the concussion thing is more important than just a game or two.

"We consider him only a short-term risk at the moment and we'll just see how he goes."

Meanwhile, ruckman Jarrod Witts (finger) and first-year draftee Brayden Sier (back) will not be available for selection this week.

Both players are expected to be sidelined only in the short-term, while Balme officially put a line through Jamie Elliott, Tom Langdon, Jackson Ramsay, Matt Scharenberg and Dane Swan for the rest of the 2016 season.