The 21-year-old back combines playing on the wing for the Blues with his medical studies at the University of Wales, Cardiff.
In his first full season with the region he has scored six tries and earned a Wales call-up, winning his first cap in the RBS Six Nations win over Scotland.
“Things have gone really well for me this season, I’m a local boy and can’t imagine playing for any other side,” said Roberts. “I’ve played a lot more games for the Blues than I thought I would and getting the Wales call was a massive bonus.
“I’m working hard on my game and fingers crossed I’ll have more of a chance at fullback next year, but I’m happy to play anywhere in the team.”
