The midfielder has been out for eight months after suffering an anterior cruciate ligament injury.
"It has been a long time, eight months, but I'm back now feeling strong and ready to kick on so hopefully everything will be all right," said Gardner to Villa's website.
"I don't think you lose it. If I see a sight at goal I'll shoot. It's just a case of getting my match fitness back.
"I'm happy to be back and hopefully I can push on now.
"Once it is healed you are stronger than before so it is just about getting your match fitness up and playing games again."