Ortiz was out of Wednesday's lineup and said the injury has been bothering him for a little while, but the series finale in Seattle over the weekend is when it really started to aggravate him.
"The day off was all right, but yesterday, I couldn't run," said Ortiz, who is hoping to miss no more than a week. "I was limping really bad. I finally came to the doctor, [and he] checked me out. ... We're just going to get some treatment. It's not anything crazy."
Papi said the training staff gave him some medication Sunday that initially helped, but he's had a little bit of inflammation above his right heel.
"It bothers you for pretty much everything," he said. "Even when I'm walking, it bothers me. It's not a good feeling. It's very painful."
Ortiz will stay in the boot for a few days, though he expects to be back in Boston's lineup by the end of the team's upcoming eight-game road trip.
"The doctor said it's pretty normal in people that exercise and things like that," he said. "They deal with that everyday. It's not like I have an Achilles problem or anything. It's just aggravation from running and doing all that kind of stuff."
Jed Lowrie and Carl Crawford split DH duties on Tuesday, going a combined 0-for-6 with four strikeouts. Adrian Gonzalez was in Wednesday's lineup as the DH, allowing Kevin Youkilis to shift over to first and Lowrie to play third.
Manager Terry Francona said he'll use the DH as a way to rest his regulars, though Gonzalez, who has been nursing a sore neck, may see consecutive days off later in the season.
"For the most part, I don't think Gonzie really likes [to DH]," Francona said. "But I think today is a day he'll happily do it. ... And [his neck] may have cut into his power a little bit, but you play and continue to play."
Jason Mastrodonato is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.