McKinnon (knee) had surgery Tuesday, Matt Maiocco of NBC Sports Bay Area reports.
McKinnon hasn't provided details on the surgery, apart from stating that it doesn't directly involve the torn ACL and damaged meniscus that wiped out his 2018 campaign. He'll now miss another full season on injured reserve, but he hopes to make it back next offseason and stick around with the 49ers. Doing so likely would involve a pay cut from his scheduled $6.5 million base salary for 2020.