Key forward Josh Bruce will miss around six weeks due to bone stress in his lower back.

After pulling up sore after training on Thursday, the 25-year-old was sent for scans which revealed the extent of the injury.

Speaking to media at RSEA Park on Saturday morning, Senior Coach Alan Richardson said that while changes were planned for this week’s team following the loss to the Crows, injury made some of those decisions for the selection committee.

“Clearly we weren’t pleased with the overall performance last week and when that happens you’re looking to improve the team and improve the performance, but some of our changes were forced,” Richardson said.

"Unfortunately for Brucey, his form hasn't been great, but it looks like it's going to be an extended period out now, with a stressy of the back.

"Something like about six to eight weeks, which is disappointing for him and disappointing for us, obviously.

“He’s become a really important person around our footy club, primarily as a player but also as a leader. It’s disappointing not to have him there, there’s no doubt about that."

Bruce had been carrying soreness but there had been no major concerns about him playing through that – information Richardson made sure to get from his medical staff.

"You can imagine all those questions get asked, given his form over the last couple of weeks wasn't great," Richardson said.

"My understanding was he'd been a little bit stiff but was really comfortable that he was physically right to go. It clearly went to another level on Thursday (at training)."

Bruce now joins Jimmy Webster (hip), Tim Membrey (knee) on the injury list.