Captain Aaron Ramsey is set to miss Wales' Euro 2024 play-offs after being ruled out for a month through injury.
The Cardiff City midfielder was thought to have sustained a minor calf strain but manager Erol Bulut has revealed it is a more severe tendon issue.
Wales host Finland in their Euro 2024 play-off semi-final on 21 March, with a potential final at home to Poland or Estonia five days later.
"They [medical staff] told me four to six weeks," said Bulut.
"I got a report it was a strain but yesterday I heard it was not a strain on the muscle, it was on the tendon.
"He will be available maybe the end of March."
Ramsey had only made two substitute appearances for Cardiff this month after returning from a knee injury which had kept him out since September.
Asked if this latest injury, sustained during training, would rule him out of Wales' play-off semi-final next month, Bulut said "yes" before adding: "This is also disappointing for us and for Ramsey.
"I will support him every way I can. I know how he's feeling. It's not easy for a player to be out for five months, come back, play and get injured from nearly nothing.
"He is also disappointed, I can understand it's injuries upon injuries.
"But I will support him till the end. I hope he can come back as quickly as possible. He has the quality we need.
"For Cardiff he is an important player, for Wales he is an important player. When you do not have that quality on the field, for all coaches he is a loss."