England bowler James Anderson has been ruled out of the rest of Lancashire’s Specsavers County Championship clash against Durham after sustaining a calf injury.

Anderson was forced to leave the field after pulling up during his run up on the third morning of the match.

The 36-year-old, who claimed his 950th first-class wicket on Monday, stretched and attempted to run in three times to shake off the problem, but was forced to leave the action.

The ECB said in a statement: “Jimmy Anderson has sustained tightness to his right calf. He will take no further part in the game and will continue to be assessed.”

With the first Ashes Test against Australia less than a month away, any potential injury to England’s star bowler will be a major concern for the selectors.

While England’s one-day international squad have been in World Cup action, Anderson has spent a prolonged spell with his county in preparation for the Ashes, which begins at Edgbaston on August 1.

This match at Sedbergh School – the County Championship’s newest venue – is Anderson’s sixth game in the competition and his two wickets on Monday took his tally to an impressive 30 for the season.

Lancashire assistant head coach Mark Chilton revealed Anderson was in good spirits despite the setback.

He said: “Jimmy has been sat with an ice pack on but he seems fine and reasonably jovial.

“With any bowler if they feel something abnormal we would much rather they came off and get assessed rather than take it a step too far.

“He has been very well managed with regards to his bowling loads and his overs and I think that has been managed expertly right throughout the season.”