EXCITING first-year Carlton forward Charlie Curnow's season could be over with a medial ligament injury expected to sideline him for four to six weeks.

Curnow, pick No.12 in last year's NAB AFL Draft, was injured when teammate Levi Casboult fell across his right knee during the third quarter of the Blues' loss to the Sydney Swans last Saturday.

"Scans have revealed it is a medial ligament injury," Carlton football manager Andrew McKay told carltonfc.com.au on Tuesday afternoon.

"We're still not completely sure on what timeframe he'll be out for. But it will be somewhere between four and six weeks, which means he's a chance to come back just before the end of the season but there's also a chance that he won't be back."

Curnow has played six senior games in 2016, but could have played more had he not been sidelined for a lengthy stint with glandular fever during the middle of the year.

McKay also said Marc Murphy was one week away from being considered for selection.

The Blues skipper has been sidelined with a lingering ankle injury since Carlton's round 10 win over Geelong.