Slater has been on the comeback trail since re-aggravating the shoulder issue in March last year, shutting down his entire campaign.
He managed seven games in 2015.
The 278-game veteran said in December his shoulder was not back to full strength and cast doubt on his prospects of returning to rugby league.
But Ryles said he was progressing well, having returned to full contact at training this month.
"He's training really well. He's started his contact so he's in pretty good shape at the moment. He's increasing his contact every week," he said.
"He's been back in full training for quite a while now. Hopefully he translates that into a good NRL season."
Ryles said Slater's return would allow Cameron Munster to shift into a ball- running role, with the stand-in fullback training at five-eighth in the off- season.
"There's certainly a huge bonus having Bill back and also having Cameron Munster as a bit more of a runner," he said.
- AAP