"I'm sure he's sore," manager Mike Redmond said. "We'll know more in another day or so, when he throws his bullpen and plays catch."
An X-ray on Saturday came back negative, and Alvarez is receiving treatment. The right-hander, who was selected to the All-Star Game, says he anticipates being ready to go at Atlanta.
"I've got to give it a couple days to see how it heals," Alvarez said. "But as of now, I'm looking to pitch in Atlanta."
Alvarez will test his leg Monday, his scheduled throw day. Redmond noted if the team's ace needs another day or two, that also could be an option.
"I'm anticipating him being able to make his start," the manager said. "If it's sore, then we have the flexibility to push him back a day, to give him an extra day. Whatever he needs."
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter