It's highly unlikely he can lose to Roller.
Roller cant take him down. Could he even take Taveres down? Nowadays Melvin has some of the best tdd in the game. He's about 10x faster than roller. You think Taveres was owning roller on the feet? Melvin might kill him. Melvin has demonstrated that he now fights with caution and reservation. I dont see him putting himself in a position for Roller to capitalize.
at -265, I already have him in a lot of parlays. I'd have him in my parlays up to -400. Maybe even take him straight later.