"He had a couple injections and took a couple of days off to let that calm down," Braves general manager Frank Wren said. "The one thing that [former Braves manager Bobby Cox] and [head athletic trainer] Jeff Porter both said was, 'This is one tough guy to play with what he's playing with.'"
Wren believes Lee tore the ligament in late August or in one of the first few games he played in September. The 35-year-old first baseman still hit .304 with three homers in the 29 games he played after August concluded.
"Derrek wasn't 100 percent," Wren said. "There wasn't really a time after that first week that he was here that he was 100 percent, and it made it tough on him. He was a gamer, and he played when a lot of other guys wouldn't."
Lee, who will likely sign elsewhere as a free agent this winter, was scheduled to have his thumb examined via an MRI exam Thursday.
Right-hander Kris Medlen was also scheduled to have an MRI to determine why his left hip has bothered him for more than four months. Medlen will be sidelined until at least August while recovering from Tommy John surgery.
Mark Bowman is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.