Nathan Stoneman has been snapped up as a permanent member of the Sheffield side.
Stoneman, 20, currently rides for Kent at National League level and he will take the place of Jack Parkinson-Blackburn who has now officially quit the club.
Parkinson-Blackburn has found life tough at Championship level and wants to focus on rebuilding his confidence with Birmingham in the Development League.
Stoneman rides as a guest replacement against Redcar but will officially become a full team member for Saturday’s trip to Glasgow.
Sheffield co-owner Damien Bates said: “We knew we had to make a move because we only had a facility to bring in guest riders for so long.
“It’s a shame and very disappointing about Jack because we have invested a lot of time and money into him to make him an asset of the club.
“But we have to move on and respect his decision to focus on the National League to try and rebuild his confidence.
“We welcome Nathan to the club, he’s an ambitious lad who wants to give it a go at this level and fair play to him for that.
“When we spoke to him about doing it he didn’t need long to make his mind up and he will give it his very best.
“His attitude is very positive and that’s what we want in our pits, he deserves to succeed and we will do whatever we can to help make that happen.
“We looked at various riders who could come and fill the slot but it was important for us to have a rider who wants to do it and wants to try and take his career forward.
“We’re at an important stage of the season now and we need everyone firing on all cylinders to help us kick on. We’ve done reasonably well so far, with the odd exception, but we need to be on a roll when the time comes for the business end of the season.”
Sheffield head to Redcar tonight after last night’s Owlerton clash fell victim to the weather.
Club officials tried everything to get the meeting on because of their fixture pile-up but admitted defeat at 4.30.