ALLEN Christensen will miss eight weeks of action after breaking his collarbone in Saturday's loss against Carlton.

Brisbane Lions medical staff initially thought the 25-year-old midfielder would miss just a month, but scans revealed the break was worse than first thought.

Christensen was crunched by Blue Andrew Walker just before half-time when the teams met at Etihad Stadium.

Lions' head of physiotherapy Shane Lemcke said it was a complicated break that was needed surgery last Saturday night.

"He is recovering well but it will keep him out for quite a while given the severity of the break," Lemcke told lions.com.au.

Young defender Hugh Beasley will also miss eight weeks after spraining his knee in the NEAFL at the weekend.

Rookie ruckman Archie Smith was concussed in the same match and will be monitored through the week.

The Lions are expected to welcome back key defender Harris Andrews to play Fremantle on Saturday, while midfielder Rohan Bewick and defender Darcy Gardiner are also in the frame for selection.