"I feel pretty good," Peralta said. "I've been running on the field. Did a couple of sprints today, and it feels 100 percent. I don't feel anything right now. It's going to be ready tomorrow."
In a season of wild inconsistencies, Peralta was at his best on Tuesday at Washington, dueling the Nats' Stephen Strasburg for six innings before the bad hamstring forced Peralta's exit. He said later that he had been feeling tightness since the third inning.
Peralta promised to be honest with the medical staff when he returns to action on Tuesday.
"If I don't tell them, it's going to be worse if we keep pushing it," he said. "But so far, I don't feel anything. I feel 100 percent right now."
Adam McCalvy is a reporter for MLB.com. Read his blog, Brew Beat, and follow him on Twitter at @AdamMcCalvy. Kevin Massoth is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.