The prop joined Rovers on loan from Wigan in May, making 13 appearances, and has impressed the coaching hierarchy enough to have secured a permanent contract.
“I’ve enjoyed every minute of my loan period here and I think this is a great opportunity for me,” the 24-year-old told Rovers’ official website.
“It wasn’t easy to leave Wigan, I have a lot of respect for what they did for me and the way they brought me through their academy, but I felt it was time for a change and I’m looking to kick on now at Hull KR.
“Every pre-season is massive, it’s about getting back into shape and getting to the maximum level you can be, but this will be a really big pre-season for me. I need to start well, especially for the fans, and hopefully I can get straight back into it.
“We want to be competing in that top eight next year and it’s a massive opportunity now for the younger players like myself to step up to the plate.
“We’ve lost Tony Puletua and we know the presence he had on the field, but we’ve got a good young pack who are all a similar age and there’s a chance to build around that on the field.
“We’ve got some great backs who get the praise for what they do on the outside but we need to set the platform for them. That’s our job in the middle and we’re looking forward to the challenge.”
Robins coach Chris Chester is delighted that a player of such potential has committed his future to the club.
“James is a strong young forward with a good offload and a real physical presence out on the field, so we’re pleased he will be continuing his development with us next season,” he said.
“He’s shown what he can do this year with some consistent game time, but after a full pre-season with the rest of the team I’m confident we’ll see even more from him in 2016.
“We are grateful to the Warriors for allowing him to join us permanently from next season and would like to thank everybody at the Wigan club for their ongoing support.”