But O'Brien said: : "Kevin is worth his weight in gold.
"He is very under-rated and can ruffle the feathers of any defender.
"I know because I have played against him a few times and he has been fantastic for the team.
"Even though he hasn't scored many goals this season he has been a real handful.
"He has shown what he can do on the international stage against Bayern. But he has been doing that week in, week out for Bolton."