It is the second time the 20-year-old has suffered the injury, having previously had the same problem in his left knee in December 2009.
Dutch centre-back Vlaar also spent two separate spells on the sidelines after he broke down with cruciate knee ligament injuries while at former club Feyenoord, but has come back stronger.
“You look at Ron now and he’s like a machine and he has done the injury twice. It just gives you confidence that you can come back,” Gardner told the Express & Star.
“So many players have done it now; I don’t know what it is, whether it’s the game being so quick now. But to know that they can get you back, the surgeon I have, Andy Williams, I’ve got massive respect for him. He’s got me back once and I know he’ll get me back again.
“It’s been six weeks since the injury and a month since the operation. I’m doing fine, I’m walking around, I’m swimming and cycling so hopefully in a couple of months I’ll be running and then five or six months I’ll be back playing.
“It’s hard to say whether I’m ahead of schedule because it’s a big injury. I’ve had this injury before and I’ve came back from it. So the main thing is that I come back stronger than I was. I know I will be. It’s just about time, it’s too early to say whether I’m ahead of schedule yet.”