Could have been simple economics, he reached the end of his contract and Derby thought his wages/signing on fee could be better spent elsewhere.
I hadn't realised he was 29 years old, I don't suppose he's going to get any better now. Bong marshalled him pretty well but I did like his aggression...
It's a shame we didn't get Jamie Ward when we had a chance, he looked tenacious, quick and skilful at times. Antonio will go to a Low end PL team and will be on big money.