SCANS have confirmed Fremantle skipper Alex Pearce has suffered a fresh fracture in his arm during the Dockers' 50-point win over Melbourne.

Pearce, who was playing his first game back one month after undergoing surgery on the same arm, left the ground after copping a heavy knock in the third quarter. 

Scans on Monday revealed a new fracture in the radius bone of his left forearm, with no timeline set for his return.

"Unfortunately, Alex has suffered another fracture of his left radius after an incident in the third quarter against Melbourne," Fremantle footy manager Joe Brierty said.

"It's really disappointing for Alex who made such a strong return in the opening three quarters of the game.

"Our medical team will now consult specialists to consider the best intervention in collarboration with Alex and we will then have a better understanding of Alex's return to play timeline."

Pearce was wearing a protective guard but appeared sore on the bench before being substituted out following the heavy knock.

The Dockers' statement win against the Demons moved them into the top four ahead of the Western Derby this weekend.

After the match, Dockers coach Justin Longmuir said the club was confident young key defender Josh Draper can step up if Pearce was sidelined again. 

"It's sore. The game was done, so we thought we'd sub him off. He has to get a scan and we'll go from there," Longmuir said post-match. 

"(Pearce is) probably a little bit nervous (and) he's a little bit frustrated. 

"Being the captain of the club and being in such good form all year, he wants to be out there competing with his brothers.

"Draper's is in good form and he's played a lot of footy. If he gets another opportunity, I'm sure he'll be ready to take it."