"I think I'll be ready," Headley said.
Ready to play Thursday, after being a late scratch on Tuesday and then Wednesday as he didn't start as a precaution, giving his shoulder an additional day of rest.
Headley, a switch-hitter, said his shoulder felt a lot better Wednesday than it did the day before, and that he could be available to hit right-handed Wednesday.
"It was important that everything that was needed to take place, took place," he said prior to the Padres' game against the Diamondbacks at PETCO Park. He also said his shoulder only bothered him when he hit left-handed.
Headley thinks he injured the shoulder in Sunday's loss on the road against the Dodgers when he tried to run down a double in the gap hit by Andre Ethier.
"Chase feels better today than he did yesterday," Padres manager Bud Black said. "We want to make sure when he comes back, there's no doubt in his mind, physically or mentally."
Headley is tied for second on the team with 25 hits and is hitting .255 overall with two home runs and 11 RBIs. He is hitting .220 as a right-handed batter and .286 as a lefty.
With Headley out of the lineup, the Padres had Scott Hairston in left field Tuesday and again on Wednesday.
Corey Brock is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.