Henrikh Mkhitaryan missed Manchester United's draw against Stoke City as a result of a thigh injury, with the club requesting his withdrawal from Armenia's two World Cup qualifiers as he continues his recovery.
The 27-year-old has only started one match since signing from Borussia Dortmund in July and has not played since the derby defeat to Manchester City on September 10.
There had been hopes he would return for Sunday's 1-1 draw against Stoke on Sunday after he had tweeted that he was back in training and close to full fitness, but was again absent from the matchday squad.
Armenia, though, have released a letter sent by United's club doctor Steve McNally that explains Mkhitaryan is still recovering from a thigh problem.
"Henrikh is still undergoing late stage rehabilitation from the left thigh muscle injury that he sustained earlier this month whilst playing for Manchester United," read McNally's remarks.
"Although his progress has been good over the past week, he is participating in limited aspects of team training and is not yet able to train fully without restrictions or play competitively.
"In view of that I would be grateful if he could be allowed to withdraw from the national team for the forthcoming training camp and FIFA World Cup qualifying matches in order to remain in Manchester to complete his rehabilitation."
Armenia are at home to Romania on Saturday in Group E, before facing a trip to play Poland next Tuesday.
The statement added that Mkhitaryan would "probably" miss the double-header following United's request.