Mariners' Luis Castillo Made 1 Pivot That Could Change Everything

The Seattle Mariners feature one of the best starting rotations in all of MLB. Bryan Woo was a breakout star last year, while Logan Gilbert is an ace-caliber starter. Meanwhile, veteran Luis Castillo is still a reliable starting pitcher as well. According to Ryan Divish, Castillo made a potentially impactful adjustment during the offseason.

"Luis Castillo changed up his offseason regimen to focus on his velocity and maintaining it. He was consistently around 94-96 mph with his fastball. In past years, it took a few outings to get to that point," Divish wrote on X (formerly Twitter).

Seattle's rotation is projected to be among the best in the entire sport. The rotation features a quality combination of up and coming stars as well as reliable veterans. A big Castillo campaign would help the pitching staff find even more success -- which is a frightening thought for opposing hitters.

What to Expect From Luis Castillo in 2026

Castillo, 33, has been somewhat overlooked in recent years given how much talent Seattle's pitching staff currently has. A three-time All-Star, the right-handed hurler has been one of the more consistent pitchers in the game over the years.

The Mariners have been able to rely on Castillo without question. He has made at least 30 starts in each of the past three seasons. Castillo has also pitched to ERAs in the mid-3s during that stretch.

The 2025 MLB season saw Castillo pitch to a strong 3.54 ERA across 180.2 innings of work. He struck out 162 hitters as well. While he was not an All-Star, it was still a productive overall season for the veteran right-hander. The Mariners would not have found as much success as they did without him.

One has to wonder if he will be even better in 2026 given the aforementioned potential velocity increase. Castillo did not strike out as many hitters in 2025 as he has in the past, so perhaps he will record more strikeouts during the '26 campaign.

Regardless of how many strikeouts he records, Castillo is going to play a crucial role in the rotation. The Mariners may feature some starters with higher ceilings than Castillo at this point in his career, but it is difficult to find a veteran who is as reliable as Castillo.

Meanwhile, the Mariners will play their next game at spring training on Saturday against the San Diego Padres, with first pitch scheduled for 3:10 PM EST.