Matthew Kreuzer will mentor the likes of emerging ruckman Tom De Koning at the Blues. Picture: AFL Photos

CARLTON'S ruck stocks have taken a further blow, with promising youngster Tom De Koning sustaining an ankle injury upon the club's return to contact training on Monday.

De Koning was in contention to replace the injured Matthew Kreuzer for the team's round two clash with Melbourne on June 13, with the veteran fracturing his foot following a fall in the side's season-opening loss to Richmond in March.

The athletic De Koning had been tipped to challenge Kreuzer for the ruck position at Ikon Park this season following an impressive summer on the track, but is now expected to miss four weeks due to the lateral ankle sprain.

06:47

With Kreuzer set to also be sidelined for up to four months due to his injury, new recruit Marc Pittonet now looms as the likely starting ruckman upon the resumption of competition.

Pittonet was recruited to the club from Hawthorn during last October's Telstra AFL Trade Period, having played seven games in five years with the Hawks.

FIXTURE REVEAL New timeslot, primetime crackers, double-headers

Carlton is also likely to be without Caleb Marchbank for the start of the recommenced season in just over a fortnight's time, with the key defender still being plagued by bone bruising to his knee.

Marchbank missed the side's round one defeat to Richmond having copped a knock to the knee in the Marsh Community Series and remains hampered by the frustrating injury more than two months on.