SEATTLE -- One of the Mariners’ most notable accomplishments last season was their rotation’s remarkable health, not losing a starter to the injured list all season. But just two games into 2023, that streak has ended.

Robbie Ray was placed on the 15-day IL with a left flexor strain ahead of Saturday’s game against the Guardians, one day after he looked and felt off in a 9-4 loss in which he walked five, consistently struggled to locate his fastball and experienced diminished velocity after pumping 94-95 mph in the first inning.

Ray, who had arguably the best Spring Training among Seattle’s pitching staff, said that he didn’t begin experiencing pain until the second inning and that he “felt really good” warming up in the bullpen. By the end of his outing, he’d surrendered five runs (three earned) on four hits. His walk total matched his season high from 2022.

“It felt a little tight, but that didn’t seem out of the ordinary,” said Ray, who didn’t mention any tightness in his postgame media session. “It’s just one of those things where it was a cold night, and I just thought maybe it took me a while to get loose there in the second. I didn’t really think that much about it. But then after that, my arm started to tighten up a good amount.”

Ray flagged Mariners athletic trainers before heading home, then he woke up on Saturday still feeling sore, which prompted him to undergo an MRI that revealed the Grade 1 strain.

Neither he nor the staff rooted the specific moment or reason that caused the injury. He didn’t throw the new splitter that he unveiled this spring -- a pitch that had a reputation for causing arm issues years ago -- but he said that was because there weren’t many counts that dictated it.

“Cal [Raleigh] never called it,” Ray said. “I never really thought about it. Lately, my splitter has been really good. I've kind of leaned on it pretty heavily, so really no issue or why I didn't throw it. It was one of those things where this is a [Cleveland] team that also puts the ball in play pretty well. So it was one of those things where there was not going to be a whole lot of swing-and-miss, and I just didn't want to mess around with it.”

The lefty will be shut down for two weeks while receiving daily treatment then will be re-evaluated. He’ll also need to build back arm strength once healed, probably necessitating a Minors rehab assignment. Team officials estimated that Ray should return in 4-6 weeks.

“I’ll start the throwing progression as long as there [are] no issues or not feeling anything in there,” Ray said. “The biggest thing is just taking the time to rest and take care of it and let it settle down.”

In a corresponding roster move, lefty Gabe Speier was recalled from Triple-A Tacoma. But it’ll be Chris Flexen, who was deliberately stretched out as a starter in Spring Training to account for attrition, who will take Ray’s spot in the rotation. That spot comes up again on Wednesday against the Angels, who will start Shohei Ohtani.

“We talked about how fortunate we were last year that we stayed healthy in our rotation,” manager Scott Servais said. “It was key. Fortunately for us, we have Chris Flexen. That’s certainly why you hang on to guys, just knowing how valuable they can be throughout the course of the year.”

Ray, who’s in the second year of a five-year, $115 million deal, had never been on the IL with an arm-related issue since debuting with Detroit in 2014.

“It’s just one of those things that happens,” Ray said. “I take care of my body. I take care of my arm. I’m in the training room almost every day just doing maintenance. Stuff like this happens. There’s not a whole lot you can do to prevent it.”

Beyond the early-season timing, it’s a frustrating individual development for Ray, given that he ramped up his throwing program much earlier this offseason, arrived at Spring Training trimmer and was throwing harder than everyone. He was also eager to put the stinging finish to his season last year behind him.

Now, the 2021 AL Cy Young Award winner will look to overcome a career first and return to a rotation that, at full strength, could be one of the league’s best.