Nathan Hrovat will sit out this week's game against Carlton after sustaining a small fracture to his thumb at training.

The small forward injured himself while tackling team mate at Arden St, and could miss the next two-to-three weeks according to GM football Cameron Joyce.

"It's a very small fracture and specialist advice is that he won't need any surgery at this stage," Joyce confirmed.

"We're hopeful that he'll only miss a few weeks, but it could also be less depending how he recovers. It's hard to put a timeframe on at this early stage."

The Roos take on the Blues in Hobart on Saturday night and are expecting key defender Robbie Tarrant to play.