The 20-year-old has had to watch from the bench since recovering from an injury earlier in the season, the form of Kevin Kyle, Stephen Elliott and Callum Elliot giving him no cause for complaint about that situation.
But, while not ruling out the possibility of Glen going out on loan, especially when such deals can now be done on a one-month basis as emergency cover for SFL teams, Jefferies says the player could still have a big role to play as Hearts bid to sustain their challenge to the Old Firm.
"Gary is still very much in our thoughts, he's just been a bit unlucky," said Jefferies.
"Big Kyle and Stephen Elliot have been doing well, as has Calum Elliot, who is having to sit on the bench as well at the moment.
"But, with strikers, they can go off the boil and perhaps even pick up an injury.
"So we will think very carefully before we do anything as the last thing I want is to get a couple of injuries and find we can't get back a player who we've just put out on loan.
"We still have a lot of thoughts about Gary being an asset for us for the rest of the season."