Tuimavave finished the 2016 season at six after starting the year in the centres but now has a rival for the position following Kelly's move from cross-city rivals Hull KR.
Both were included in the team's starting 13 when the Airlie Birds' squad numbers were handed out last week but Radford insists he will not be held to what is on a player's back when he selects his side.
The coach admits he is keen to again utilise Tuimavave in the halves and says he is looking forward to the selection headaches that having Kelly around will provide.
"Carlos finished the year at stand-off but he's very comfortable playing in the centres," he said. "It will be a tough battle but it's one I'm looking forward to watching.
"Albert is very much like Jamie Shaul; he tends to put himself in the right place when other guys are carrying the football, and I'm sure he's going to add a lot of strike to what we've already got in the locker moving forward."