Dr. James Andrews performed surgery on Griffin's right knee on Jan. 9.
Griffin suffered a sprained lateral collateral ligament in an win against the Baltimore Ravens in Week 14 and then tore his LCL and anterior cruciate ligament in a wild-card playoff loss to the Seattle Seahawks.
"I've been real mum on talking too much about RG III. He wants his recovery to be fairly private but I can tell you he's way ahead of schedule. His recovery has been unbelievable so far," Andrews told ESPN. "RGIII is one those superhumans. First patient I ever had like that was Bo Jackson. And recently I, of course, had Adrian Peterson, who is also superhuman. They have an unbelievable ability to recover, where as a normal human being may not be able to recover."
Redskins coach Mike Shanahan did not put a timetable on Griffin's return but said he would not play unless he is 100 percent.
"For me to tell you anything at this time is kind of ludicrous," Shanahan said earlier this week. "All I can tell you, though, is when you've got a guy who's got the flexibility that he has, he's got the strength, he's got the desire to be the best at what he does, usually good things happen."Griffin, the AP 2012 NFL Offensive Rookie of the Year, threw for 3,200 yards with 20 touchdowns and five interceptions last season.