Much is expected of the young Scot as Albion head into the big time and winger Thomas is sure he will deliver.
He told the Birmingham Mail: "I think he is ready. I think he was the best midfielder in the Championship last year.
"He just needs to get a good pre-season under his belt and it's good that we've got a long rest because he played a lot of games last year.
"It will be good for him to rest and recuperate and come back and pick up where he left off.
"I think he's happy. He's had a good season but at the same time he has to prove it in the Premier League now."