Bannister, 22, joined Widnes in the close season but suffered a broken leg in pre-season and has struggled to force his way in to the Vikings line-up.
Matt Calland has snapped him up on a short-term deal and he will go straight in the squad for tomorrow’s clash with Featherstone.
Calland said: “Steve’s not had the best of luck recently, but he’s got a lot of talent.”
“He’s an attacking back rower with a low centre of gravity that makes him really difficult to tackle.
“He had a fantastic game against us when he was on loan at Whitehaven from Saints a couple of years ago and he’s someone we’ve kept an eye on.
“We’ll assess him this week and he could come into contention against Featherstone.
“He’s not coming with a guaranteed spot. It’s up to him to work hard and show us what he can do.
“If he impresses, there’s a possibility that we could look at signing him on a longer term deal. The ball is in his court.”