Despite a strong 9-2 win over the Athletics on May 26, the Mariners are struggling internally. While the local media tried to subdue the noise in the clubhouse, visual evidence suggests otherwise. And now a veteran starter is expressing frustration with the manager’s decisions. 

Luis Castillo had pitched just four innings on Monday when the team replaced him with Bryce Miller on the mound. He couldn’t contain his anger as he entered the dugout. He first removed his jacket and threw it on the bench, and then picked up a cap and shoved it on the jacket. 

Manager Dan Wilson wanted Castillo and Miller to share the pitching duties in the same game and thus implemented a piggyback strategy. But neither pitcher was happy with the decision.  

Castillo, who signed a five-year, $108 million contract with the Mariners in September 2022, can extend it to $133 million and 2028 with a vesting option: he needs to pitch 180 innings in 2027. But given his current role as a reliever, that seems highly unlikely. What makes this more painful is that before this season, he had never pitched out of the bullpen in his 10-year MLB career.  

He served as a reliever for the first time on May 19, pitching only 2.1 innings. Asking a 3x All-Star with over 1,400 innings pitched hasn’t made a good impression on Castillo. 

“As a competitor, you want to go out there and just continue, but at the same time, we knew that was part of the plan,” he told The Seattle Times’ Adam Jude. 

The situation has been quite similar to Miller, who started in all 74 games in his career before this season. He entered the mound out of the bullpen for the first time on Monday. 

“This setup is not very comfortable,” Miller said, expressing his discontent about piggybacking Castillo. 

Notably, the Mariners aren’t the only team with this strategy. We have already seen the Mets and the Dodgers implementing the same this year. Carlos Mendoza designated veteran Sean Manaea for a flexible hybrid role in the rotation. Similarly, Dave Roberts had put Justin Wrobleski and Emmet Sheehan on multi-inning piggyback duties to ease the burden on the elite starters. But none of them faced a backlash of this level as they tried it with young prospects.

Wilson is asking two highly successful starters to alternate relieving roles. That’s exactly what stemmed the frustration among the duo. But the pitching combination isn’t the only problem for the Mariners. 

Seattle’s discomfort grows far beyond its unusual pitching strategy

The Mariners lost Cal Raleigh to a right oblique strain on May 12. He was going through a hitting slump earlier, but just as he had overcome that, he made the IL for the first time in his career. And Seattle didn’t just lose a player; it lost the de facto captain. 

His absence behind the plate and in the dugout has forced a highly stressful stretch for the team, as the Mariners have lost six of their 11 games. They called up Jhonny Pereda from the minors, who has registered just one RBI so far. 

The overall offense is also struggling as the team is 27th with only a .227 AVG in the league. Its late-game power metrics are also among the worst. What that means is that Seattle is pressuring its pitchers and defense.

While the pitching isn’t the best, a +13 run differential implies the team is doing its job. But the current record after the 9-2 win against the A’s is 26-29. And the Mariners are the only team holding the second position with a win percentage of under .500. 

That is not a comfortable scenario for the franchise. As Seattle struggles to establish consistency, the internal discomfort is taking the team further away from all-around performance.