Miguel Castro becoming dominant force in Mets' bullpen

When the Mets dealt for Miguel Castro right before the trade deadline last Aug. 31, it didn't create much of a stir.

Castro, who was acquired by now-former GM Brodie Van Wagenen, came to the Mets after showing flashes but getting spotty results in parts of six seasons with the Toronto Blue Jays, Colorado Rockies, and Baltimore Orioles.

After joining the Mets late during the 2020 season, Castro displayed his tremendous stuff, but his control -- he walked roughly five batters per nine innings in five-plus seasons before the trade -- remained a huge issue.

Something seemed to click during spring training of 2021, though, and Castro entered the regular season as one of the Mets' main late-inning options along with Edwin Diaz, Trevor May, and Aaron Loup.

That Castro found himself in a back end role so early this season likely had something to do with the absence of Seth Lugo. But regardless of why he ended up there, he has been a mostly dominant force.

We wrote before the season that the Mets' bullpen could turn into a true strength if Castro harnessed his elite stuff, and that's exactly what he's been doing so far.

In eight appearances over 8.0 innings, Castro has a 2.25 ERA (0.34 FIP) and 1.25 WHIP with 14 strikeouts (15.8 per nine) and just two walks (2.3 per 9).

On Sunday against the Washington Nationals at Citi Field, Castro -- using his filthy mix that includes a fastball that reaches triple digits, a changeup, and a slider -- struck out three batters to work around a pair of hits in a scoreless appearance.

And on Tuesday against the Boston Red Sox, he struck out two in a perfect frame.

A LOOK AT THE ADVANCED NUMBERS

Castro's fastball has averaged 98.4 mph this season, while his changeup (91.1 mph on average) and slider (86.0 mph) have also been plus offerings.

Batters are hitting literally .000 against his slider so far this season.

They've had better luck against his changeup and his fastball, but a lot of that seems like early-season statistical noise.

Batters are hitting a ridiculous .500 on balls put in play against Castro (his career BABIP allowed is .277). And per Baseball Savant, when hitters have made contact so far this season against Castro, they have hit the ball incredibly hard.

The good news for Castro and the Mets regarding the above is that those hard hit rates don't seem close to sustainable. There's also the fact that hitters haven't made contact very often.

SWING-AND-MISS STUFF

Castro is using his changeup more than ever this season, throwing it roughly 28 percent of the time as it has become his most used secondary offering.

And Castro has done a terrific job keeping his changeup and slider away from the middle of the plate.

Meanwhile, he's throwing more first-pitch strikes (66.7 percent) than ever and inducing more swings and misses than ever.

Overall, Castro's strikeout rate is in the 96th percentile, and his whiff rate is in the 93rd percentile as he has adeptly used his secondary stuff to complement the fastball he throws close to half the time.

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Along with Diaz and May, Castro has helped keep the Mets' bullpen afloat with Lugo out. Jeurys Familia has also pitched well, with five straight scoreless appearances.

For Castro, the stuff has always been there. It was simply a matter of him being able to harness it while keeping his walks down.

So far in 2021, Castro looks to be emerging not only as a reliable option in the late innings but a potentially dominant one.