Scotland manager Craig Levein admits captain Darren Fletcher might not be back in his squad for the crucial matches against the Czech Republic and Lithuania unless he makes "exceptional" progress following illness.
The midfielder was excluded from Levein's squad for the friendly against Denmark, which takes place at Hampden next Wednesday, as he builds up his fitness following a mystery virus.
Levein said: "It's extremely difficult for me if he's not playing for his club to include him in the squad. I have spoken to Darren twice in the last two weeks just to make sure he's progressing."
Fletcher missed two months of last season's run-in for Manchester United, although he played 90 minutes against Blackpool on the final day of the Barclays Premier League campaign.
The 27-year-old was left out of United's tour part for their pre-season trip to the United States in order to work on his fitness back at the club's training ground.
Fletcher last week declared himself "fighting fit" but Levein feels the player needs games before throwing him into the Euro 2012 qualifiers at Hampden.
Scotland host the Czechs on September 3 before Lithuania visit three days later, and Levein's men realistically need to win both matches to keep their play-off hopes alive before facing Liechtenstein and Spain away the following month.
Levein added: "I'm in constant contact with him. I went down to meet him at the end of last season and had a long chat with him. I desperately want him back in the squad, more than anybody, but he has to have played some football.
"I can't just put him back in the squad because he's a good lad. I think it's important he is back on the field for Manchester United and back playing 90 minutes, and also gets his confidence back because he has been out for a long time.
"I hope to have him available for the October matches and if things go exceptionally well, then I'll have a look at it again for the September games."
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