Newcastle United boss Alan Pardew feels Steven Taylor's development has stalled.
The former England U21 penned a new deal with Newcastle earlier this year.
"Steve had a fantastic younger part of his career and then he's hit a bit of levelling-off when he's not gone forward or backwards," said Pardew.
"That can be dangerous for a player.
"He needs to get his career moving in the right direction again.
"He's a young centre-half with tremendous qualities and he must have the mentality to use those.
"We've changed his training programme and his diet because he was getting too muscular on top.
"We've tried to slim him down a little bit and he looks better for that. He looks quicker.
"Steve's got the technical ability to become an England player but to do that, you've got to be fit every week.
"Unfortunately his fitness and injuries have been a big issue and probably one of the reasons he's flattened out."
