SEATTLE -- Luis Castillo joked on Tuesday afternoon at T-Mobile Park that if anyone saw him dancing in the coming days, that would be the sign that he’s doing just fine.

But unfortunately for “La Piedra” and the Mariners, Castillo's good spirits didn’t prevent him from landing on the 15-day injured list with a Grade 2 left hamstring strain ahead of Seattle’s series opener vs. San Diego, relating to the issue that forced him to exit Sunday’s start in St. Louis.

The club also announced that it selected the contract of backup catcher Seby Zavala from Triple-A Tacoma and transferred reliever Yimi García from the 15-day IL to the 60-day IL.

The club did not immediately announce a corresponding move, and the hope is that Castillo will only miss the allotted time and return before the end of the regular season. But for at least two turns through the rotation, the Mariners will have to fill the void of their two-time Opening Day starter.

“Talking to the trainers, they think it's not out of the question that he could be ready by the time the 15 days are up,” Mariners general manager Justin Hollander said. “He’s a fast healer. He felt stronger and better already today. … I don’t have a definitive timeline, except to say that it could be 15 days or it could be longer."

The severity of Castillo’s injury was revealed after he underwent an MRI during the team’s off-day on Monday. Castillo then played catch with an athletic trainer on Tuesday but without leveraging much of his legs. He also received a platelet-rich plasma injection.

This is the first time the three-time All-Star has experienced a hamstring injury.

“Nothing like this ever happened [to me],” Castilo said on Sunday through an interpreter. “But I mean, anything can happen to an athlete like this.”

Castillo’s next turn would have been Saturday against the Rangers, and with off-days on Monday and Sept. 26, it’s possible that the club could reslot its rotation and only have to use a replacement twice. Hollander indicated that Seattle would decide each assignment case by case.

The leading candidate to slot into Castillo's spot would presumably be Emerson Hancock, who served as the de facto fill-in for Bryan Woo when he began the season on the IL. Lefty Jhonathan Díaz is also on the active roster, having rejoined the Mariners when rosters expanded on Sept. 1.

Castillo sustained the injury on Sunday on his 57th pitch as he was coming down and through his delivery and as Iván Herrera stole second base. The pain intensified over the ensuing two pitches, at which point catcher Mitch Garver could see something was wrong. Garver called for Mariners head athletic trainer Kyle Torgerson, who conferred with Castillo and then walked him to the visitors' dugout.

“That last pitch is when it felt worse,” Castillo said. “So that's what I decided to just stop so it wouldn't get any worse.”

Castillo has been a beacon of health since joining the Mariners at the 2022 Trade Deadline, making every start since. He's pitched 175 1/3 innings this season and carried a 3.64 ERA. He surrendered two runs in the second inning on Sunday.

The Mariners have mostly avoided significant injury scares this season. Castillo made his 30th start on Sunday, Logan Gilbert and George Kirby have each made 29 and Bryce Miller has made 28. Woo has been the only outlier, having missed the first six weeks with right elbow inflammation and then another two-plus weeks into early July with a right hamstring strain.

“Our guys do a great job of taking care of themselves in between starts, making sure they're prepared to go out and carry the workload for a full season,” Hollander said. “And obviously, there's some luck involved, too, between the players themselves and our training staff. They have been incredibly dedicated to being out there every five days.”