Stewart has two years of his Old Trafford contract to run and recently failed to win a move to Rangers.
DECISIONS DECISIONS
"There has been contact with Hearts but it's very early days," the 23-year-old Stewart told the Scotsman.
"I don't even know if United will be willing to let me go because for the Rangers deal it was all about me reaching a settlement on my contract."
"I've still got to speak to the gaffer (Sir Alex Ferguson) to get his thoughts on the whole thing and that's going to be the be-all and end-all for what happens next.”
"Hearts is a possibility, without doubt, but until I've got some guidance from the gaffer I really don't know what my position is."
Stewart is a boyhood Hearts follower but the Edinburgh club could only afford a small contribution towards the player's reported £12,000-a-week salary.