The 32-year-old signed for the Hoops during the summer on a free transfer after his contract expired at newly-promoted West Ham.
It prompted former QPR first-choice keeper Paddy Kenny to move to Leeds United, however, Green endured a disappointing start to the campaign, conceding six goals in two games.
Hughes secured the arrival of Champions League winner Cesar on a four-year deal from Internazionale this week, leaving Green’s future already in doubt at Loftus Road.
The QPR manager admitted the chance to sign Cesar was too good to turn down and hinted Green could be allowed to quit the club if he was unhappy at being back-up to the Brazilian.
“That isn’t my concern,” Hughes said. “That may concern Rob in terms of his international standing but from my point of view I have got to make sure we are strong as a club.
“If in the future any of my keepers came to me and said they felt their future lay elsewhere then we can have a conversation about that and make a decision that benefitted everyone.
“But at the moment it’s early days and the challenge is there for all my keepers.
“It’s a difficult situation for Rob but the opportunity to bring in Julio Cesar came very quickly and it’s one that we felt as a club we couldn’t ignore.
“On a football level and a business level, we needed to do it because you don’t get opportunities like that very often.”
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