Shelton was brought to the Lane from Helsingborg for £1.85m by Neil Warnock when he was at the reins of the club when United were in the top flight. Luton has joined the Norwegian outfit for a fee of £1m with a sell-on fee included in the deal.
The fee could also rise if Shelton succeeds with Valerenga. Blades Gaffer Kevin Blackwell said: "Luton wasn't exactly the player I was looking for, he was a bit of a maverick. This opportunity arose for him to play regularly and is just what he needs at this stage of his career."
Shelton didn't make and impression in front of the Bramall Lane faithful but their was a few memorable moments. Just like the balloon saga in the FA Cup tie with Manchester City at Bramall Lane. Lee Martin's cross took a deflection off a gathering of Man City balloons which took the ball away from the feet of Michael Ball which consequently let Shelton tap in from close-range.
His best performance by a mile was against Manchester United at the Theatre of Dreams. He caused the back line many problems and looked very impressive. He looked like he was to be a Blade hero if he put in performances like that day in day out but that wasn't to be and Shelton has had to move on.