Gardner left local side Birmingham to join Sunderland for £4.7million in June after scoring 10 goals at St. Andrews last season.
The 25-year-old midfielder complained of feeling homesick and missing his family in the Midlands.
According to the Daily Mirror, Birmingham will test Sunderland's resolve this month with a loan bid.
Birmingham manager Hughton said: “When the window closes, there will be some Premier League clubs that have players who are not getting regular games who will be surplus for whatever period.
“We still have that open to us. Maybe a month on a short loan.”