"Villa had an option to buy me but Martin O'Neill said he was a bit unsure, that he wanted to look for a more experienced keeper," said Carson.
"But for someone like myself who is 22, I needed someone to say 'you've got my confidence, you've got my backing' and, having spoken to the manager at West Brom (Tony Mowbray), he gave me a lot of confidence and hopefully I can repay him.
"I really enjoyed my time at Villa but, like I said, they wanted a more experienced keeper and went down that route.
"O'Neill said he was still interested but I couldn't go somewhere maybe just to be second choice. I'd have been better off staying at Liverpool in those circumstances."