Goalkeeper George Willis has signed his first professional contract with the Blades today (Friday).
The 17-year-old Rotherham-born stopper has penned a two-and-a-half year deal, with the option of a further year.
Willis, who has represented England in the Victory Shield, provided goalkeeping cover for George Long for much of October and November, prior to the arrival of Danny Coyne.
On committing his future to United, Willis said: "I have been with the club for a number of years, so I am delighted to have been given the opportunity to sign professional terms.
"It was a fantastic experience to be involved with the first team earlier in the season. The demands were far greater than what I've been used to but it was a challenge I relished.
"For the rest of the season I just want to concentrate on working hard in training and doing well for the U21s, then hopefully next season I can really push on."
Boss Danny Wilson added: "George is a great prospect and now that the contract business is done and dusted he can fully concentrate on progressing further.
"Darren Ward, our goalkeepering coach, speaks very highly of him and young George only has to look at George Long for inspiration of what can happen if you work hard at your game."