Andy Murray is set to miss Britain’s Davis Cup quarter-final in France as the world No.1 battles a mystery virus he apparently picked up during recent training in Miami.

Davis Cup captain Leon Smith seems resigned to fielding his second-choice team for the April 7-9 tie in Rouen which comes before the start of the gruelling clay-court season.

“I wouldn’t want Andy to rush back for the Davis Cup,” Smith told British media.

“First and foremost is his health. He’s played so much tennis in the last 12 months to get to where he is.

“There is much more than Davis Cup for him to look forward to over the rest of the year, not least three Grand Slams.”

Murray also missed the first round in February over Canada in Ottawa, due mainly to potential travel stress.

The Scot, who expended most of his energy reserves in overhauling Novak Djokovic to take the top ATP ranking spot at the end of last season, has not been truly fit for weeks.

He pulled out of the current Miami Masters due to an elbow injury after suffering with a mild case of shingles following his early Australian Open loss the in January.

Now he is battling the virus which at first prevented him from leaving Miami. So ill was the 29-year-old that he skipped an ATP Player Council meeting as well as a sponsor appearance.

The Scot had only a two-week holiday break and began the 2017 season on the back foot. Murray is now back in London for medical tests on his latest condition.