The Marlins are cautious, hoping the injury isn't more serious.
"He's sore, very sore," manager Ozzie Guillen said. "I hope it's nothing serious. We've got to wait one more day to see how he is. We'll go by ear."
Kearns tweaked his hamstring while running the bases in the third inning of Tuesday's 7-6 win over the Rockies. He scored from first on Giancarlo Stanton's RBI double. He pulled up a bit rounding third base.
Kearns went to left field for the top of the fourth inning. But he was moving slowly on Michael Cuddyer's double. At that point, he was replaced by Chris Coghlan.
Coghlan got the start in left field on Wednesday.
The Marlins already have center fielder Emilio Bonifacio on the disabled list with a sprained left thumb. Bonifacio is eligible to come off the DL on June 3.
Bonifacio says the swelling is going down and he remains hopeful of only needing the 15 days to recover.