Sunderland manager Sam Allardyce dropped Jeremain Lens from the first-team squad and has fined him two weeks' wages after the winger reportedly refused to take part in a training exercise.

According to the Daily Mail, the Netherlands international, who moved to the North-East side over the summer for £9m, "infuriated" Allardyce after he refused to warm down with his fellow unused substitutes after last week's 1-0 defeat to Watford.

The 28-year-old was subsequently dropped for Saturday's game at Chelsea and was forced to train with the Under-21 side, while the club are in the process of imposing the maximum disciplinary fine of £100,000.

Speaking about Lens last month, Allardyce suggested that he was not impressed with his work rate.

"I think what Jeremain has to do overall, like they all have to do, is to lift his level up in terms of work-rate," he said. "There is no doubt at this level of football the size of the work-rate needed. With each position, I have the levels of an elite performer and an average performer for a Premier League player. It's easy for me to monitor."

The Black Cats go into the Christmas period 19th in the table and five points from safety.