Mansfield defender Tom Naylor has been given the opportunity to try and earn a deal with Derby after being invited for a trial.
The 20-year-old centre-half, who is also being monitored by an unnamed Premier League club, played 67 minutes as the Rams reserves beat Walsall 6-1 at Belper Town's Christchurch Meadow ground on Wednesday night.
Naylor partnered Russell Anderson, making his comeback from almost a month out with a groin injury, at the heart of Derby's defence while Conor Doyle and David Martin returned to action after ankle injuries suffered in pre-season.
Anderson played the full game and opened the scoring, while Callum Ball, Chris Maguire, Alex Witham and Tomasz Cywka (2) were also on the scoresheet.
Derby defender Jake Buxton, meanwhile, is poised for surgery after fracturing an eye socket in training.
The 26-year-old suffered the injury in a collision and is expected to be out for around three weeks.
It is the latest setback for Buxton, who was plagued by stomach, groin and back problems that restricted him to just one substitute appearance last season.
He recently returned to action after another groin injury in Derby's opening reserve-team fixture against Port Vale last month and played for an hour.