FORT MYERS, Fla. -- Red Sox ace Chris Sale has been ruled out for Opening Day and is expected to start the season on the 15-day injured list, interim manager Ron Roenicke said on Thursday.

Sale is not injured, but he is building back to a regular Spring Training progression after dealing with the flu and pneumonia for two weeks just before camp opened.

If the Red Sox back-date Sale’s IL stint by three days, the earliest he can make his 2020 debut would be on April 7 at Fenway Park against the Rays.

Sale hopes to start the first day he is eligible.

“I mean, [my target date] was March 26,” said Sale. “Especially given what happened last year and going through this offseason, that was my goal. I wanted to be there. I’ve let other people do my job and pick up my slack for long enough.”

As much as he hated to give ground with what Roenicke and the training staff recommended, Sale agreed it was the right move.

“It was a gut punch,” Sale said. “When we were in that meeting, I said the only thing this hurts is my ego, and that doesn’t matter. How can you argue with them just trying to take care of me and do what’s best, not only for myself, but for the organization and the team moving forward? They had great points and I didn’t. I respect that. Like I said, I respect everybody in that room and the decision was made and you move forward.”

Unlike a year ago, when the Red Sox were coming off a World Series title and former manager Alex Cora took it easy on his veteran starters during the spring, Roenicke thinks it’s important that every Boston starting pitcher make six starts before pitching in the regular season.

Given the time he missed due to illness, Sale wouldn’t have been able to do that.

“There were certain things we were allowed to do and weren’t allowed to do because of the 2018 season,” said Sale. “I think they just want me to get fully stretched out and get where I need to be. I started two weeks late, so I’ve got to stay two weeks late. Simple math will tell you that kind of makes sense. You know, do I like it? Absolutely not. Do I respect it? A hundred percent. It is what it is. You move forward and keep working.”

Considering Sale missed the final six weeks of last season with a left elbow injury, the last thing the Red Sox want to do is rush him through Spring Training so he can pitch on Opening Day.

The good news is that Sale’s left shoulder and elbow are both strong at this point in camp.

“Nothing at all with the arm,” said Roenicke. “He’s doing really good. We’re really happy with where he’s at. This is strictly for missing two weeks and then only being able to give him four starts in Spring Training.”

After a productive offseason, illness hit Sale at about the most inconvenient time possible.

“With the sickness, it cost him two weeks’ time and that two weeks is what we’d like to give him to make sure he’s right,” said Roenicke. “He’s worked hard on getting his arm right. We didn’t think four starts in Spring Training was fair to him to make him start the season. He’ll open up on the [IL].”

This would have been Sale’s third straight Opening Day start for the Sox. Though Roenicke isn’t ready to announce a replacement for Sale, Eduardo Rodriguez is the most likely choice. The lefty is coming off a breakout 2019 season in which he won 19 games.

Getting Sale back to his vintage self after a down season last year is one of the top priorities for Roenicke and the Sox, who have him under contract for the next five seasons. Sale will throw live BP for the first time this spring on Saturday. He has been sharp in all of his side sessions.

“The good thing with Chris is that he is so competitive, and he wants to start the season right off to be out there. But he’s realizing, he’s thought about this -- he knows we’re looking out after him and what’s best for him, what’s best for the team. And this really is the right way to do it,” said Roenicke. “To treat him fairly and also to take care of the club and where are with him, not just this year, but in the future -- this is the best way to do it.”

Without Sale, the only certainties in Boston’s rotation to open the season are Rodriguez, Nathan Eovaldi and Martin Pérez. The Sox were considering an opener for the No. 5 spot, and perhaps could also use one in the fourth spot until Sale returns.

“We can do it with two spots in the rotation, but we’ll see if someone emerges and covers one of those spots,” said Roenicke.

There are no obvious rotation candidates, but Chris Mazza and Ryan Weber are two that are in the mix, according to Roenicke.

Minor Leaguers, including 2017 first-round Draft pick Tanner Houck, are also getting a chance to show what they can do this spring. Bryan Mata, Boston’s top pitching prospect, is starting Tuesday against the Phillies, but he only has 11 games of experience at Double-A Portland and would be a long shot to make the team.

Don’t rule out chief baseball officer Chaim Bloom adding a starter before the end of camp. He did say he was open-minded about a possible acquisition before learning that Sale would miss the start of the season.

“We would always want to accumulate as much depth as we can. So I don’t think that changes,” Bloom said. “But at the same time, we have a lot of guys here we’re interested in learning more about, that we’re excited about, and we brought them all in for a reason. We have some guys within the organization to help them get better. This is good to see them put those adjustments into play and learn more about them.”