And despite landing on the 15-day disabled list on Friday, Headley was encouraged that his injury won't keep him from the lineup for more than two or three weeks.
"It's definitely better than it was [the day after] in the spring," Headley said. "It feels quite a bit better than I anticipated it feeling today."
In February, Headley strained his gastrocnemius muscle, which is one of three muscles in the calf. He thinks that this latest injury is in the soleus muscle of the calf.
The Padres replaced Headley on the 25-man roster with infielder Jace Peterson, who was playing for Double-A San Antonio.
Headley wasn't the only Padres player to suffer an injury Thursday, as Seth Smith strained his right groin chasing a Jose Lobaton double down the left-field line in the bottom of the 10th inning.
"When I was running toward the left-field line, I felt it tweak on me," Smith said. "I've had something similar before in Colorado where I think I missed three games."
Smith doesn't think he'll miss more than two or three games with the injury.
"I don't see it being much longer than that," he said.
Corey Brock is a reporter for MLB.com. Keep track of @FollowThePadres on Twitter. Teddy Cahill is a reporter for MLB.com. Follow him on Twitter at @tedcahill. This story was not subject to the approval of Major League Baseball or its clubs.