Fremantle defender Alex Silvagni will have hamstring surgery in Melbourne this week that will rule him out for three months.

The Freo Dockers are also exploring all possible options for Anthony Morabito as he continues to suffer ongoing soreness in the knee he has had reconstructed three times.

Silvagni initially injured his hamstring at training in the lead up to the Freo’s final NAB Challenge game against West Coast on March 22.

He returned to play for Peel Thunder in the WAFL on Sunday but re-injured the hamstring in the first quarter.

Fremantle coach Ross Lyon said on Tuesday night that the defender would require surgery.

"He tore his hamstring down at Peel and it's turned out to be worse than we thought," Lyon told Channel Seven.

"He'll fly out to Melbourne to have surgery this week. He'll miss a period of 12 weeks."

Meanwhile, Lyon said Morabito's ongoing knee issues were a serious concern but the club had not given up hope of finding a solution.

"It's incredibly tough," Lyon said.

"He's had knee soreness. He really hasn't trained all summer and we're working hard behind the scenes to try and find a solution and we're exploring the whole world, really, to try and get the best treatment for Anthony. It's not the end of the road yet but he's got some work in front of him.

"He's still a very young man with enormous talent. It's not over 'til it's over and we're exploring solutions and it's just some knee joint soreness that people work through.

"There's been some great stories like Nick Riewoldt with that. So we certainly haven't given up here. That's not what we do."

Morabito was the feel-good story of last season, returning to play three AFL games after missing three full seasons due to three consecutive knee reconstructions.

He is contracted until the end of 2015.

With the sudden retirement of Colin Sylvia, the impending AFL Anti-Doping Tribunal hearing of Ryan Crowley, and the injury troubles of Silvagni and Morabito, Lyon said the team’s depth would be tested.

"All lists need all their players available," Lyon said.

"It's certainly a challenge for us. It's a really good question because it looks like we're injury-free but then you look under the surface and we've got some challenges."