FREMANTLE defender Michael Johnson could miss up to 10 weeks after scans revealed he had suffered a severe hamstring tear in Friday night's loss to Richmond at Domain Stadium.

Johnson suffered the injury just 11 minutes into his 200th game and had scans at the weekend that revealed he would miss between eight to 10 weeks.

The 30-year-old won’t require surgery for the high-grade tear. 

Johnson, who was an All Australian in 2013, had been enjoying another outstanding season, standing up in the absence of key tall Zac Dawson. 

Click here for Doc Larkin's injury update from round 10

Dawson is still up to two months away from returning from a thumb injury, while fellow key defender Alex Silvagni is five to seven weeks away from returning from a hamstring injury.

Johnson missed crucial stages of Fremantle's 2014 season with knee and back injuries last season, including the team's finals campaign.

He has shut down forwards including Kurt Tippett, Jake Stringer and Jake Carlisle this season, also playing an attacking role at times to rank No.2 in the AFL for rebound 50s.   

Ruckman Aaron Sandilands backed young defender Alex Pearce to step in and fill Johnson's role after three weeks sidelined with a back injury.

"He's going well and he trained fully last week, so I'm sure if he gets a chance he'll put his hand up and take it," Sandilands said.

"He's a quality kid and a quality player, and he did the job a couple of weeks ago.

He's a young kid with an old man's brain pretty much … he's held in really high regard around the football club."

Pearce, who made his debut in round six against Essendon, was recruited with pick No.37 in the 2013 NAB AFL Draft.