Cespedes, 31, suffered the hamstring injury while running to second base in the fifth inning Thursday night against the Philadelphia Phillies.
Cespedes, who said it felt like a "shock" in his hamstring, was scheduled to undergo an MRI on Friday, though both he and Collins are hopeful he will miss only a couple of days.
"It's not a cramp," Cespedes said after the 6-4 loss at Citi Field. "It felt like a shock. I've had this type of injury before. This time it doesn't feel as serious."
Cespedes, who signed a four-year, $110 million deal in the offseason, is hitting .263 with six home runs and 10 RBIs in 16 games this season.
"Any time you're talking about a hamstring, it's a concern," Collins said. "When you talk about a hamstring and a guy like that, with his muscle strength, you've got to be careful."