ST KILDA concedes it didn't know the full extent of prized recruit Dan Hannebery's struggles with his body when it traded for him.

Saints coach Alan Richardson told Melbourne radio station SEN on Friday morning the 28-year-old's calves and hamstrings had been giving him grief when he hit top speed, forcing the club's fitness staff to "rebuild" the former Swan to some extent.

"We knew that he had stints where he hadn't played, we knew about his training history, or lack thereof, that he'd really struggle to be able to get the (training) time in," Richardson said.

"Did we think it was going to be as significant as this? No, we didn't.

"We did know we were getting a bloke that we needed, to some extent, rebuild, but probably not to this extent.

"But that's OK. He's here for a long time. He's not here for a short time. If it means he's not here for a month longer than we thought, that's fine."

The triple All Australian will likely return through the VFL when he is declared fit, but Richardson forecast that could be some time away.

"To some extent, he needs to be rebuilt … I wouldn't be surprised if it's longer than round four," Richardson said.

"It'll take a while I reckon. I'm hoping it'll be sooner.

"It'll depend a little bit on how he responds but right now, the response has been slow and the response has been consistent. When we get him up to 30-32km/h, he's starting to get wonky. That's going to take a little bit of time."

Richardson explained why Hannebery was experiencing these problems.

"He's been getting sore, basically anywhere to do with his legs but particularly his calves and his hamstrings. As we've upped the load in terms of the intensity, his body has just struggled," Richardson said.

"He's had two years where he just hasn't been able to put in the work. He's gone out and played without great prep because he's been able to do that for a fair while.

"He's a little warrior, he's obviously been a champion player. I reckon it's caught up with him."

Hannebery averaged 19 disposals last season, his lowest tally since his debut campaign in 2008.

Richardson believes St Kilda is on the right path to fixing Hannebery's body.

"Our guys are really confident now, that they've spent enough time with Dan and learnt from how he's responded or how he hasn't responded to whatever we've thrown at him," Richardson said.

"They know we're going to have to go right back and get this done and that's started, so we're already a couple of weeks into that."

Meanwhile, star midfielder Jack Steven looks set to face Gold Coast on Sunday afternoon at Marvel Stadium.

Steven took a 10-day break late last month to deal with a mental health issue, but has since returned to training.

His has received approval to play from that perspective, needing only to prove his fitness after being named on an extended bench for his side's season opener.

"I'm really confident Jack will play," Richardson said.

"If you'd have asked me two weeks ago, I would've been very surprised (if he'd play). He's done a remarkable job, and so have the people working with him."