Gareth Bale has been ruled out of Wales's final two crucial World Cup qualifiers against Georgia and Ireland, according to British media reports on Tuesday.
Bale's fitness has been a source of concern for the national side since he suffered a calf muscle strain against Borussia Dortmund in the Uefa Champions League last week.
The 28-year-old winger missed Real Madrid's league clash with Espanyol on Sunday but reported to the Wales camp the following morning.
Wales are second in Group D, four points behind leaders Serbia and one point above Ireland.
Two wins in the matches on Friday, away to Georgia, and next Monday, at home to Ireland, are likely to guarantee them at least a place in next month's play-offs for a place in Russia.
"The Football Association of Wales can confirm that Gareth Bale will miss the upcoming World Cup qualifiers against Georgia and Republic of Ireland," said an FAW statement.
"Bale, who missed Real Madrid's game against Espanyol on Sunday, arrived with the rest of the Wales squad on Sunday and attended Monday's annual FAW Awards dinner at the team headquarters in Cardiff.
"But following dialogue with Real Madrid, Bale was sent for a scan and results confirmed that he wouldn't be fit to feature."
Bale's absence could open the door for Liverpool teenager Ben Woodburn to make his first Wales start.
The 17-year-old player made a dramatic introduction last month when he scored the winner within five minutes of coming on as a second-half substitute against Austria.