Headley received ice treatment on Saturday afternoon and will likely have an MRI sometime Monday once swelling in the calf has subsided. The team's medical staff will know more once they receive the results of the test.
At the very least, Headley doesn't seem too concerned. Frustrated? Yes, but not overly worried about the injury.
"We'll probably know a little more in the next couple of days, but off the top of my head, it's probably going to be a couple of weeks," Headley said. "But it's not something I see being a huge issue, but it's going to take a little time."
Headley had offseason arthroscopic surgery on his left knee and has previously had a strain of his left calf, but never the right.
Last spring, Headley fractured the tip of his left thumb sliding in a Cactus League game and missed the first 14 games of the regular season. But, if anything, he has time on his side, as the Padres don't start playing games until Thursday, with Opening Day (March 30) still a long ways off.
"I'd rather have it happen now than in three weeks," Headley said. "It's frustrating. You come to camp, you feel good, you put in the work in the offseason, come in great shape and you strain a muscle. But if there's a time for it to happen, I'd rather have it happen now."
San Diego manager Bud Black sounded confident that this injury isn't terribly serious.
"It's the nature of the game, these type of things pop up over the normal course of spring," Black said. "But the silver lining is it happened on the fourth day of our spring. He'll be fine in time."
Timetables on these types of injury vary greatly.
Closer Huston Street sustained a strained left calf in 2012 that caused him to miss over five weeks of the regular season. He had the same injury a year ago but missed less than two weeks.
"We'll get a closer look [Monday] just to make sure nothing else is involved, but we're fairly confident it's just a muscle injury," Headley said.
Headley is the highest-paid player on the team at $10.525 million. He'll be a free agent after the season, but has indicated a strong desire to remain in San Diego.