Frodham, 21, joins the Vikings on a one-year loan deal, but can be recalled at any time.
Widnes Director of Rugby, Paul Cullen commented: “We are delighted to welcome Gareth to play for the Vikings in 2011.
“We hope he follows in the footsteps of Liam Farrell and uses this process to promote himself to the next level.
“We have a proven track record of giving young players a chance at the Vikings and look forward to establishing our links with St. Helens as we have with Wigan.”
“Gareth has missed a lot of rugby due to injury over recent seasons and therefore this move is part of his continuing development as a Rugby League professional.
“We hope he can gain similar benefits that the likes of Jacob Emmitt and others in the past have experienced.”
Meanwhile, the two clubs will clash in a pre-season friendly at the Stobart Stadium, the home of both sides in 2011, on Sunday 23rd January (3pm).