Belt was hurt reaching on an infield single in the seventh inning when he took a hard step after reaching first base. He limped off the field after being briefly examined by a trainer.
``Hard to really pinpoint what happened because I started feeling it when I was walking from first to second, and it buckled on me a little bit,'' Belt said.
Belt will have more tests when the team returns San Francisco on Thursday, but he said he hoped the injury was minor based on a lack of pain when trainers checked his leg for structural damage.
Associated Press contributed to this report.