John Gregory says keeping Gareth Barry is a huge test for Aston Villa.
"Villa is a huge club but it's not as big as Manchester United or Liverpool. If that group of clubs come knocking it will be hard to turn them down. Yorke went to United and I couldn't stop him. He went there and won the Treble so how can you argue with that?
"These are things Martin will not be able to promise him when the big boys show an interest."