Staker has a problem with the tendon in his left calf that inserts into the back of his knee. The veteran has no timeframe for a return.

 

He sustained the injury in the Lions' first intraclub trial in early February, and after initially hoping it was a calf issue, the news got worse.

 

It continues a horror stretch for the popular former West Coast utility.

 

Staker ruptured the anterior cruciate ligament in his right knee twice in 2011 (undergoing LARS and a traditional reconstruction), and then had surgery to remove damaged cartilage in the right knee early in 2013.

 

He has played just 22 games in the past three seasons, but looked to have overcome his bad luck by playing the final 15 last year.

 

Lions football manager Dean Warren told AFL.com.au the club had tried everything to solve the latest injury riddle.

 

"We had Jill Cook - who we've used in the past and is one of the world leading experts on tendons and the treatments of tendons and tendinopathy - here, and her colleagues were up last week for a conference," Warren said.

 

"They looked at it and were confident we couldn't have done any more in relation to the treatment.

 

"It's basically not healing as quickly as we would have hoped.

 

"No doubt it's frustrating for 'Stakes' and it's also a little frustrating for our medical team.

 

"We're confident we've done everything we can but the tendon itself is just not healing as quickly as we would have liked."

 

Staker is set to rest the injury for another week before having more treatment.

 

Twitter: @AFL_mikewhiting