Well he's got two years left, but the West Ham contract was only a third less and I'd presume 3 years minimum so the same amount of guaranteed money, and I'm sure he'd have got a contribution from United.
What wages is he going to get after another season of only a few rather poor appearances...
United should have bitten their arm off for that offer. I'm presuming they'd still have to bung slabhead half of it to compensate for the drop in wages but any deal is better than him moping about on 10 million a year for the next two seasons.