Stephenson, 21, was with the Reds since the age of 12, but now moves to the capital to hook up with the Championship 1 club.
He said: “It’s been a wrench to leave Salford, as they have been such a large part of my life for the past nine years, but I felt it was the right time to move on and challenge myself. I received a number of offers but the one from Skolars appealed the most.
“I followed their progress last season and believe the club are going places under Joe Mbu. I am ready for this fresh challenge in my life and I’m joining a club that has realistic ambitions of challenging for promotion next season.”
Skolars General Manager Howard Kramer believes the capture of Stephenson is a clear statement of intent from the club, who narrowly missed out on the play-offs last season.
They will be hoping to challenge at the top end of the table in the nine-team division in 2013, which includes three new clubs.
Kramer said: “Most key members of last year’s squad have now put pen to paper on new contracts. The club is very ambitious and supportive of head coach Joe Mbu as he seeks to strengthen the squad for next year’s challenge.