Through one week’s worth of games, the Mariners bullpen is the leading source of heartburn in the Pacific Northwest. The vacuum left by Edwin Díaz will take many Jarred Kelenic doubles and Justin Dunn strikeouts to fill, but for now we have a mishmash of prospects and misfits to slam the door. Seattle’s surprising start has been made possible by a few strong starts in the ‘pen. Matt Festa has had three impeccable outings, Roenis Elías has emerged with 95-96 and a nifty changeup supplanting his picturesque curve, and Tuesday night Anthony Swarzak offered a glimpse of what will hopefully be a guiding veteran hand.
The other steadying force thus far this year has been a player we literally couldn’t find useful film of this offseason when he first joined the Mariners. One of four Mariners to make their MLB debut in Japan, Brandon Brennan has looked intriguing on every continent he’s pitched on. It is the fate of most Rule-5 draftees to be their team’s most forgettable new face, but in Jerry Dipoto’s world he’s simply been another name lost in the shuffle. And yet now that we have video of Brennan at work, there’s an encouraging profile of the type of reliever the Mariners have been sorely lacking for several years.
Brennan’s bread and butter is his sinker/changeup combo. Now that we’ve gotten eyes on it, the sinker and changeup have looked impressive, both sporting similar movement profiles and a healthy 10-12 mph velocity gap. Here are a few looks from his two-inning blitz through the heart of the Red Sox order.
For a 6’4 guy, Brennan is a bit of a slinger. His release point consistency isn’t a thing of beauty, and the sinker has yet to tunnel particularly well with the changeup in this young season, yet the movement and location are so similar it’s been plenty effective.
He gets Andrew Benintendi there, but it’s not even his best work. Brennan’s best pitch by leaps and bounds is that circle change. He’s a good candidate to be a platoon-beater as a result, giving poor Mitch Moreland fits here:
The M’s broadcast mentioned a few times that the team’s analytics group targeted Brennan specifically for his changeup, which they felt was an elite pitch going overlooked in the White Sox system. Against righties he’s had success as well with the pitch, even when missing his spot slightly, but as we can see here his pitches flatten significantly when left up.
There’s still a lot of run there, but that’s a hitter only fooled by the velocity gap, not the movement. His entire repertoire works best at the knees or below, where it sinks most. Brennan also reportedly has an underwhelming slider, though he’s yet to use it in the bigs and it may have been scrapped indefinitely so long as he continues handling players on either side of the plate.
It’s an interesting mix that may immediately evoke Fernando Rodney comps for Mariners fans, but sadly Brennan doesn’t quite have La Flecha’s otherworldly velocity separation between his heater and change. Rodney didn’t get to being MLB’s oldest active big leaguer purely by jaunty headwear—that sinker/changeup combo has always made Fernando a reliable source of grounders, helping him earn plenty of double play balls to mitigate his famously erratic control. Brandon Sean Michael Brennan may have the name of a 3rd-round exit Bachelorette contestant, but his profile has a similarly Fernando-esque proficiency for earning grounders in spades.
That’s great news, because throughout the entire Dipoto era the Mariners have struggled to get grounders from their bullpen. From 2016-2018, only the Padres and Mets (both graced with spacious, fly ball gobbling parks) have had a lower GB% than the Mariners bullpen at 41.7%. The only relievers to eclipse a 50% groundball rate in over 30.0 IP in the season during that time were southpaws Mike Montgomery (2016) and James Pazos (2017). Lefty specialists like Zach Duke and Marc Rzepczynzski (I was promised I wouldn’t have to spell that ever again) were often relied on in key situations for grounders despite dire career-long platoon issues. The only righties to approach fitting this role have been Tony Zych and Shae Simmons, who both were waylaid by injuries. The last time the M’s had a righty with a >=50.0% groundball rate was 2015, when both Rodney and Carson Smith accomplished the feat.
Grounders aren’t the end-all be-all of bullpen success, but the ability to keep the ball on the ground gives your defense a better chance to get outs on the runners that do reach, and minimizes the chances of a stray dinger ruining the fun. Having a groundball specialist can also help shut down big innings midstream with a well-timed double play ball. The Mariners haven’t had that guy for several years, but if Brennan is anything close to what he’s looked like so far, they’ve finally found one.