Aaron Hughes has not played since being injured in September
Hearts defender Aaron Hughes is unlikely to be available for the first leg of Northern Ireland's 2018 World Cup play-off against Switzerland.
The 37-year-old was recalled to Michael O'Neill's squad after being injured for the qualifiers with Germany and Norway.
But he is set to miss Hearts' game with Kilmarnock on Sunday and is likely only to be available for the second leg.
Hearts manager Craig Levein said: "In an ideal world, I'd like him to do a week to 10 days before coming back in."
Hughes has only played six times for Hearts this season, a calf problem keeping him out since the 2-1 Scottish Premiership defeat at Dundee on 30 September.
The former Newcastle centre-half will travel with his countrymen as the squad prepares for Thursday's first leg in Belfast, and Levein and O'Neill will discuss the player's fitness before the game.
"He has been out since Dundee and has only done one day's training," he said of Hughes, who earned his 108th cap in a 2-0 win over Czech Republic in September.
"If we step back and give him his seven to 10 days of full training, he wouldn't play for us on Sunday, he wouldn't play for Northern Ireland on Thursday but might be available for their next match."
Aaron Hughes (right) last played for Michael O'Neill's side in a 2-0 win over Czech Republic
Levein has had to field a host of youngsters in his midfield as well as playing others out of position because of injuries, but he revealed winger Jamie Walker's hamstring issue is not as bad as first feared.
The 23-year-old pulled up in the second half of Saturday's 3-1 defeat by Rangers and it was suggested he could be out for at least a month.
However, Levein expects Walker to return to face Partick Thistle after the international break, along with fellow midfielders Prince Buaben and Arnaud Djoum.
"He won't make Sunday, but I am hoping that him, Connor Randall, Prince, Arnaud Djoum and Aaron will all be back for the Partick match," he said.
Don Cowie is keen to make his return from a calf problem against Kilmarnock, but Levein does not want to rush the former Scotland midfielder into action at Murrayfield.
"It's always a worry," the former Scotland manager added. "He has had problems with his calf previously.
"I can only trust that he knows best because he's an experienced player and will know where he is with regards to his fitness.
"My intention is to get him on the park if he's available."
Source: bbc.com