Wales fear David Brooks will miss the rest of their Euro 2020 qualifying campaign.
Bournemouth forward Brooks underwent surgery after rolling his ankle in a pre-season game at the end of July.
The 22-year-old was originally ruled out for three months and Wales hoped he would be fit for their final qualifiers against Azerbaijan and Hungary in mid-November.
But Wales boss Ryan Giggs says Brooks is unlikely to make those crucial dates.
"It's a difficult one because he was still in a boot in the last camp," Giggs said.
"It's looking around November. Now whether that's back playing or back actually training, I'm not too sure.
"Even if he's on the bench or fit for Bournemouth the week before it will be difficult to pick him because he's been out for so long."
Wales resume their Euro qualifying programme in Slovakia on Thursday before entertaining Group E leaders Croatia in Cardiff three days later.
Giggs' side are four points adrift of Croatia and three behind Slovakia and Hungary, with a game in hand on their rivals.
"We've always been playing catch-up, but we want to go into the last camp with it in our hands," said Giggs, whose side have six points from four games after last month's home win against Azerbaijan.
"At the start of the group you would think that 15 points would get you qualified.
"But it changes all the time because everybody keeps beating each other, and you just have to look after yourself.
"We could come out of these games with a couple of draws and still have a chance.
"But then it's out of your hands, and ideally, we'll win the games."
Giggs has had enviable attacking talent at his disposal with Gareth Bale, Daniel James, Harry Wilson and Brooks all having played their part in the campaign.
He also hopes to call on Aaron Ramsey for the first time in Euro 2020 qualifying this week as the Juventus midfielder is finally free of injury.
"You can't play them all (attackers)," Giggs said.
"A lot of the criticism was aimed at my style of play after Azerbaijan, but you don't know until the Sunday night who you're going to have and little time to work on stuff.
"You have to take it all into consideration because you can't play four wingers or three number tens.
"We're very blessed in those positions but it's finding the right balance."
