Not successful at first, since most MMA fighters now know BJJ, and there's a growing legion of fighters who are experts at it. Royce would be in the Welterweight division, which is loaded with grappling talent, including several BJJ Black Belts. read more
Some of the answers already explain why a prime Gracie would probably only have median success in today’s UFC. The sport has moved on from trying to solve which style is the best. None of them are, since they all have strengths and weaknesses. read more
Gracie gained fame for his success in the Ultimate Fighting Championship. Between 1993 and 1994, he was the tournament winner of UFC 1, UFC 2, UFC 4, and fought to a draw with Ken Shamrock in the championship match in the Superfight at UFC 5. read more