Reliever Diego Castillo Heating Up for Seattle Mariners

After struggling heavily through the first few weeks of May, Seattle Mariners reliever Diego Castillo has put together three consecutive scoreless appearances.

To start the month of May, Diego Castillo was roughed up in his first three outings against the Astros, Rays (giving up five runs without recording an out), and Phillies, and appeared to be at risk of potentially being sent down to Triple-A Tacoma. Losing his spot in Seattle’s bullpen would have certainly been disheartening, as the M’s sent off promising infield prospect Austin Shenton to the Rays for Castillo at last year’s trade deadline.

However, the big righty has rebounded in tremendous fashion over his last three appearances: he struck out the side in the 8th inning of a win over the Athletics on Monday, held the A’s hitless on Wednesday, then pitched a brilliant hitless ninth in this afternoon’s loss to the Astros.

After writing a few weeks ago about Castillo’s drop in movement on both his sinker and slider this season, his movement on those pitches has actually continued to digress; however, he’s recently been able to locate on the edges of the strike zone with more effectiveness, allowing for more room for error in the extensiveness of his pitches’ breaks.

Interestingly, Diego Castillo’s sinker is producing quite a few more swings and misses than it did last year, as it’s jumped from a 10 to 15% whiff rate this season. For a pitch to be breaking less than usual but causing more hitters to swing and miss, it’s obvious that Castillo is beginning to locate with much more precision; a good sign for a bullpen still searching for its best options in leverage situations.