France captain Patrick Vieira admits he "does not know what to think" after being struck by yet another injury setback.

The Inter Milan midfielder has experienced an injury-plagued last 12 months but looked to be back to his sharpest during the past few weeks.

However he felt a pain in his right calf while warming up ahead of Les Bleus' World Cup qualifier against Romania in Constanta on Saturday and was forced to withdraw from contention minutes before kick-off.

Vieira claims his latest injury is not serious but it has left him perplexed and exasperated.

"Frankly, I don't understand," said the former Arsenal midfielder, who saw a niggling thigh injury keep him out of Euro 2008 this summer.

"Over the last few weeks, I have felt really good. I came here on the back of some very good performances for Inter so I just don't know.

"I don't know what to think. I felt a pain in my calf as if I had been kicked - except I hadn't been touched!

"To miss such an important match was of course very frustrating. But I am trying to stay positive and telling myself that there are still a lot of great matches to be played for France."

Vieira will fly to Italy on Monday so Inter's club doctor can make an assessment of the midfielder's injury.

He has already been ruled out of France's friendly with Tunisia in Paris on Tuesday.