CARLTON'S start to 2018 has gone from bad to worse with captain Marc Murphy set to miss the next month with a foot injury.

Murphy will at least miss games against West Coast, the Western Bulldogs, Adelaide and Essendon as the injury to his left plantar fascia heals.

The 30-year-old was forced out of the Blues' loss to North Melbourne on Saturday night after the injury – which he'd been managing – "popped" during the warm-up.

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Scans have since revealed he'll need at least a month on the sidelines to allow the band of tissue to recover.

"Scans have revealed he's done some damage to his plantar fascia, which is the material that runs along the bottom of the foot," Carlton football manager Andrew McKay told the club's website.

"The doctors are saying he'll be out for the next four weeks, which is really unfortunate for us and Marc, but it gives someone else an opportunity to fill that spot."

In better news, recruit Darcy Lang (ankle) and defender Alex Silvagni (hamstring) are close to returning from injury but will have to wait another week as the Northern Blues have a bye this weekend.

"Darcy's made some real progress over the last few weeks," McKay said.

"He's available for selection although he's been out of football for quite some time, so he won't be available for senior selection.

"Silvagni's progressed really well over the last couple of weeks. He'll probably sit out for another week, which won't do any harm, and then be available for selection next week."

Fellow defenders Caleb Marchbank and Tom Williamson are also recovering from injuries with Marchbank three weeks away after rolling his ankle against Collingwood in round three.

Williamson is also considered to be three weeks away as he rehabilitates a back injury, as is Ciaran Byrne, who is coming back from the quad he strained against Gold Coast.

Former Port Adelaide ruckman Matthew Lobbe has joined defender Sam Docherty in running drills after battling a pre-season hamstring injury.

Lobbe will start training next week with a view to being available the week after that.

Docherty is said to be "progressing well" after his November knee reconstruction.