Fuld was slated to see a doctor Monday night and then would have a better idea of when he could return.
Manager Joe Maddon said he doesn't want to rush back the 30-year-old.
"We can't just push him back out there," Maddon said. "We want to get him well and utilize him in the playoffs."
Fuld said he had actually tweaked the hamstring during Friday's win at New York but continued to play through it, believing it would eventually subside, until the fifth inning of Sunday's matchup when he was trying to reach first on a grounder hit to Robinson Cano at second.
"I knew it was kind of going to potentially be an issue," Fuld said. "That's sort of why I was maybe not running 100 percent down the line. I saw Cano bobble that ball and my instincts just told me to turn it up a notch, and my body didn't agree with that."
Fuld said he's never had to deal with a hamstring issue before, which makes him unsure how soon he'll be able to recover. The outfielder did say that he would likely be able to hit before running, but he did not know when that would be.
Fuld has played sparingly this year after missing the first three and a half months because of right wrist surgery. In 39 games, he has a .273 average with five RBIs and seven stolen bases.