Paul Jewell has warned Robert Earnshaw to roll his sleeves up but Giles Barnes to leave his socks down if they are to start proving their Barclays Premier League potential. The Derby County manager believes there are too many players who are more concerned with image than performance.

Neither Earnshaw, Derby’s record £3.5 million signing in the summer, nor Barnes, for whom the club reportedly rejected a £6 million bid from West Ham United, earned a regular starting place under Billy Davies, who was succeeded by Jewell last month.

The new manager held a meeting with Earnshaw, who scored 14 goals for West Bromwich Albion when they were in the top flight in 2004-05. “I’ve had chats with each of the players and said you have to impress on me that you need to be in the team and that starts in training,” Jewell said. “Robert Earnshaw’s goalscoring record is good. I want to see more off [the ball work] from him. I want to see more from every player here; it’s up to me to get as much as possible out of them.

“Giles Barnes has got the potential to be a good player. He’s young, he’s confident - he’s got a long way to go. He has got a big future if he channels his talents. He’s got bundles of talent but there’s more to it than talent.” Jewell believes that young players can get sucked into the hype of the Premier League. “Some are followers of fashion, more interested in how they appear than in how they play,” he said. “That winds me up.

“Thierry Henry started wearing his socks over his knees and all of a sudden you see players at all levels doing it. The easiest thing to do is to wear your socks up like Henry; the hardest thing is to play like he can.”