Roberts signed as an undrafted free agent with the Raiders on Thursday.
Roberts played four seasons for BYU and averaged 53 catches for 828 yards and five touchdowns over his final two campaigns. He has good height at 6-foot-4 but lacks vertical speed. Las Vegas has one of the league's least-established WR corps, so Roberts could compete for a roster spot as a depth wideout if he impresses in training camp.