Radford, who handed Jamie Shaul the number one shirt for 2015, is understood to have been hugely impressed with the attitude and numbers posted by new signing Curtis Naughton in the opening week of testing.
Teenager Naughton joined the club last week after a year in Australia with Sydney Roosters and is understood to have hit the ground running at the Black and Whites.
The 19-year-old arrived at the club last week having prepared for his new venture with his own individual training programme in Australia. He is understood to have impressed the coaching staff in particular with the times he has set in sprint exercises.
It's the type of headache Radford will welcome, with Naughton arriving to put pressure on Shaul, and also provide competition for places in the outside backs if needed.
Hull now have three players challenging for full-back in pre-season, a role Shaul impressed in last year having been entrusted with the responsibility by Radford.
Half-back Jordan Rankin told the Hull fans' forum last week he intends to challenge Shaul for the number one shirt, while also competing for a more familiar role in the halves.
The arrival of Leon Pryce and Marc Sneyd has increased the competition in the halves, and Rankin, who has previously played full-back for Hull and impressed with his running game, has told Radford he wants to challenge for a place both there and at full-back.
Having been away on a two-day team bonding camp last week, which involved the reward of a paint-balling session on Friday, Hull's players face a tough week of training at their Chanterlands Avenue base.
