According to NFL Network's Ian Rapoport, Garoppolo did not need any other ligaments in his left knee repaired when he went under the knife. Rather, doctors merely found "some other minor damage" that was not a cause for concern.
"He was very pleased with the way it went," 49ers general manager John Lynch told KNBR 680-AM, per the Mercury News' Cam Inman. "It's one of those deals where it looked better–because sometimes you see some things on MRIs you don't know–but it was a good repair and they’re very optimistic about his prognosis for the future."
ESPN.com's Adam Schefter added Garoppolo is expected to be out six to eight months, which would put him on track to return in time for training camp.
"I'm hoping that he'll be able to get into OTAs and do some non-contact stuff with throwing the ball and everything," head coach Kyle Shanahan said, per Schefter. "It's always a little bit better when you're dealing with a quarterback and stuff as opposed to other positions, because you can get them in hopefully in seven-on-seven drills a little bit early and things like that, which helps those guys get involved a lot faster."
While the face of the franchise recovers, the 49ers will trust stopgap starter C.J. Beathard to lead the offense.
Beathard, now in his second year out of Iowa, threw for 298 yards, two touchdowns and two interceptions in last week's 29-27 loss to the Los Angeles Chargers.
He will make his second start of the season—and seventh of his career—Sunday against the winless Arizona Cardinals.