It wasn’t the rookie year Melvin Gordon wanted or expected to have.

The B1G’s all-time single-season rushing leader fell short of expectations in his first year in San Diego. He rushed for just 3.5 yards per carry (the Chargers were last in the NFL in that category) and he still doesn’t have an NFL touchdown yet. On top of that, Gordon finished the season on injured reserve after tearing cartilage in his knee.

The former Wisconsin star had offseason knee surgery, but the San Diego Union-Tribune reported that it was actually more serious than originally believed. As it turned out, Gordon had microfracture surgery, which has a scary association in the NFL.

After reports surfaced that UCLA linebacker Myles Jack might need microfracture surgery, he fell from a possible top-five pick to the second round. Former No. 1 overall pick Jadeveon Clowney saw his rookie season come to a sudden end because he needed microfracture surgery. Reggie Bush had the same procedure done in 2008, but he was able to return to form.

It’s a dangerous procedure for a running back because it entails making small holes in the bone to regrow cartilage in the knee. Repairing cartilage can make for a sometimes lengthy rehabilitation process, and there’s no guarantee a running back will have the same mobility.

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Gordon had his surgery performed by the world-renowned Dr. James Andrews, who operated on Bush, as well. While it might have a serious association, each surgery varies in severity.

“Typically, I know especially in the NBA and the NFL, when people hear ‘microfracture surgery,’ they are going to think it could be a potentially career-ending injury,” Dr. Brian Schulz, an orthopedic surgeon at Kerlan-Jobe Orthopaedic Clinic in Los Angeles told the Union-Tribune. “Normally, it’s more directly related to the size of the defect, what’s going on in the rest of the knee. If it’s a relatively small lesion that’s localized to a specific point, the microfracture has worked pretty well, even in professional athletes. … I don’t think microfracture is quite the kiss of death that everyone makes it out to be.”

That’s good news for the former first-round pick. Gordon was participating in drills at off-season training camp on Monday.

The timetable for recovery is four to six months, which Gordon said he’ll have no problem reaching.

“I’m getting better. I’m getting better,” Gordon told the Union-Tribune. “I’m not where I want to be, but I think I’m ahead of schedule. I’m sprinting pretty well. I’m cutting. … No question, I’ll be ready for training camp. I’m not even worried about that.”