He told the Birmingham Post: "He has benefited this summer from having a complete rest in pre-season and he looks a really good player for us at the moment.
"He did show well in our first year when we took him on loan and then he did his knee ligaments.
"He then did particularly well to get back for the World Cup last year, but it was too early. I think trying to get back for the World Cup hindered him.
"I am always a believer that if you are out for a year, which he was, it takes you a year after that to get back into your stride.
"But, he's doing very well for us right now."