The South African-born tighthead, who had been outstanding in National Division One, made his first team debut in the EDF Energy Cup against London Irish in December and first appearance in the Guinness Premiership against Newcastle Falcons last month.
Ruwers, who stands at 6ft 2in and weighs 19st 5lbs, has enjoyed previous spells with Natal Sharks and Atlantic Pumas.
Director of Rugby Mike Ruddock said: "We are pleased to announce that Shaun has decided to stay at Warriors for the next two years. Shaun is definitely a fine prospect at tighthead and can also play at loosehead.
"He still has a way to go before he could consider himself a genuine first team starter. However, we feel that it is worth giving the investment in Shaun's continued development to help him become the player we believe he could be.
"Tony Windo will be responsible for his future development in his role as assistant forwards coach and I'm sure Tony will be able to help Shaun to achieve his goals."
Ruwers said: "I have enjoyed my first season with Warriors and I'm pleased to sign a new deal so I can continue my development at the club.
"I have enjoyed working with the coaching staff and I'm determined to repay the faith they have shown in me by working hard on my game and being a success for the club in the Guinness Premiership."