"It was one of those nagging deals that he could play with," Bochy said. "It was bothering him some. It's that time of year. You heal up, get cleaned up with some surgery and get ready for spring."
The Giants skipper added he believes the tear happened slowly throughout the season and couldn't pinpoint an exact date as to when the injury occurred.
"It was just a gradual thing," Bochy said. "He had been getting treatment on it. I think you could look at a handful of those guys [in our clubhouse] who probably have a little tear."
The expected recovery time for Belt's injured knee is approximately four weeks, Bochy said, which coincides with his return to baseball activities from the concussion.
"The timing is good," Bochy said of Belt's procedure. "After surgery, you just have to be quiet and lay down for two or three days. It was still going to be a little while before he could do some baseball activities."
Bochy said he feels the injury affected his first baseman at times, but Belt's numbers masked whatever soreness he was dealing with.
Belt hit .280 while setting career highs with 18 home runs and 68 RBIs in 2015.
• Bochy said Tuesday that Nori Aoki would see a concussion specialist Wednesday, but clarified Wednesday that the outfielder is in Pittsburgh and will see the doctor Thursday. Given the Giants' inability to reach the postseason, Aoki will more than likely rest for the last week of the season.
• Tim Hudson is scheduled to start Thursday, but the Giants manager said it will be "short work." The veteran right-hander figures to pitch only a few innings in the last start of his career.
• Bochy would not commit to Madison Bumgarner making one last start this year in the season's final game.
"I need to talk to Madison," Bochy said Wednesday. "I'll probably have news on that tomorrow."
Oliver Macklin is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.