Berkman was appearing at Memphis' AutoZone Park, where he is rehabilitating a sore right knee with the Cardinals' Triple-A affiliate.
"I don't want to rule anything out. But if you asked me right now I'm leaning toward not playing next year," Berkman told the paper. "I don't want to say for certain because I don't want to do like Brett Favre and say, 'I retired; I'm not retired; I'm retired; I'm not retired.' I don't want to make that call right now, but if you put a gun to my head and demand an answer today I would tell you I'm probably not going to play next year."
Berkman, 36, who will appear in five Minor League games over a seven-day period with the Triple-A Redbirds, is testing his damaged right knee that required surgery in May and was then reinjured when he was hit by a Clayton Kershaw pitch.
While Berkman knows his knees aren't 100 percent, he hopes to rejoin the Cardinals on Sept. 1 and provide bench depth for the team in the final month of the season.
"I'm [on rehab] largely out of a sense of obligation to be available to help the team and to help the organization," Berkman said to the paper. "It's about the guys and the Cardinals organization. It's not a personal thing about me wanting to win another World Series. Obviously, that's everybody's goal. But I don't want it to be about me personally. It's about being part of this team."
In the game, Berkman walked and grounded out twice in three plate appearances while playing five innings in the field.
"It's not like a physical hurt that I can't move," Berkman said of his knees to the paper. "It's waking up every morning with sore knees, sore back and just feeling old," he said. "When you're young it's easy to summon the will to battle through that.
"The older you get and the fatter and happier you get, the harder it is to do it. It requires a lot of will. And if I don't have it, I don't have it."
Berkman hit .301 to go along with 31 home runs and 94 RBIs during the 2011 season with the Cardinals.
Quinn Roberts is a reporter for MLB.com This story was not subject to the approval of Major League Baseball or its clubs.