The injury has kept Gardner out of action since mid-September but it is believes that a return to first team football with the Tigers is just around the corner.
"Anthony Gardner is making good strides, but you're looking at a couple of months now that he's been out," Hull boss Phil Brown told the Hull Daily Mail.
"He'll need a match or two either behind closed doors or in the reserves - that's the same for Craig Fagan.
After breaking his leg in November, Fagan has made a great recovery.
"Come Christmas, it could be two presents waiting for me because they will feel like new players," Brown added.
"Craig's now back on the training ground with the physio, but he's not had any physical contact. If we can get a full week out of him this week, maybe we could see him on the training ground next week.
"Knowing Craig, he'll be looking at Sunderland which is great news for me. He looks very fit and he was born an athlete, but match fitness is a different thing."