"It's not a big deal," Duda said. "In a couple of days, I should be going."
Duda is available to pinch-hit, but Collins wants to give him a chance to rest.
"I just said, 'Look, we've got to get your leg right,'" Collins said. "Because if your leg is affecting your hitting, if it's affecting your trunk rotation and everything else, than it's got to get fixed."
Duda, who is hitting .247 and is tied for the team lead in home runs, with 12, said the hamstring has been bothering him for a few weeks. He hoped the issue would be resolved during the All-Star break, but Collins said it "stiffened up."
Duda has slumped throughout July and is hitting .143 with just one extra-base hit in eight games this month. Collins said that Duda hasn't used the injury as an excuse for his recent struggles.
"He will say no," Collins said. "I'll support that, but I'll imagine it hasn't helped."