"We were spot-on with the injury as far as diagnosing it in training camp," Ford said, according to ESPN's Nick Wagoner. "I had a severe case of tendinitis. ... With my position, that's a blown tire. I feel great right now. I'm able to actually explode off of this knee.
"Thinking back on it, I can't believe I played a whole season on it, and we knew at the end of the day what we had to do. It had to be surgical, but I didn't want to miss the season. We had too much going on. I didn't want to miss that. It's in the bag now, though, I'm confident in that."
Ford added that he's unsure of a timetable for return due to the chronic nature of the knee issue.
The 29-year-old was in and out of the lineup in his first season with the 49ers due to quadriceps and hamstring ailments, as well as the aforementioned knee injury. He racked up 6.5 sacks in 11 games but was only able to play over 50% of defensive snaps in one contest, per Pro Football Reference.
The 49ers traded a second-round pick to the Chiefs last March for Ford, who was immediately rewarded with a five-year, $85-million deal.
San Francisco's dominant defensive line has already lost DeForest Buckner, who was traded to the Indianapolis Colts this offseason.