40 in 40: Justin Topa, the Mariners’ new mystery man in the bullpen

Lost somewhat in the shuffle of the Mariners signing AJ Pollock to a one-year deal is a quieter deal that went down just hours before, when the Mariners traded away pitching prospect Joseph Hernández, the anchor of the 2022 Modesto Nuts rotation, to acquire the services of Justin Topa from Milwaukee.

If your first reaction was “who?” despite considering yourself a true roster-trawling baseball sicko, don’t be too hard on yourself. Because of a series of elbow injuries—in addition to a pair of TJ surgeries that held him up on his way to the bigs—Topa has an incredibly limited track record. At the ripe old age of 31, Topa has pitched a grand total of 18.1 MLB innings—although he’s logged about 250 minor-league ones. That means he’s still in pre-arb, and even has MiLB options remaining at an age where many other players are testing the free agent waters for the first time.

Because of his limited track record in the bigs, finding publicly available data for Topa’s pitch characteristics is difficult, and what’s available is cursed by the bugaboo of small sample size. Topa hasn’t thrown over 100 instances of any single pitch in the big leagues; in fact, Justin Chamberlain’s venerable Pitch Leaderboard lists about 200 pitches by Topa total since the 2019 season, divided about 70-30 between his sinker and slider. Baseball Savant is helpful in providing the expected numbers against the actual, suggesting where some noise might be in the results:

While there’s obviously some noisy noise in these numbers, there are some concerning aspects, as well. A 269-point drop in xSLG vs. actual slugging is great, but as the money people say, half of a really, really big number is still a really big number. But again! These are some pretty petite sample sizes. Let’s tunnel a bit deeper into Topa’s arsenal.

Digging into the pitch characteristics of his primary pitch, the sinker, more deeply on Alex Chamberlain’s pitch leaderboard, there isn’t anything that especially suggests a unicorn pitch: his VAA (Vertical Approach Angle) for the sinker is -5.7°, somewhat on the flatter side but not at all an outlier, especially compared to VAA king Paul Sewald (-3.5°) or even fellow new bullpen addition and former teammate Trevor Gott (-4.2°). However, unlike Sewald, Topa does crank the sinker up to 95 mph, and was even higher (97.5 mph) with the pitch in 2020, when the Brewers yo-yoed him back and forth between the alternate site and American Family Field, so if there’s more of a velocity rebound for him, getting tricky with a riding fastball probably isn’t necessary. That’s a big if, and could make the difference between Topa being a helpful, workmanlike bullpen addition, and something truly special.

Consider the difference between 96 and a near-miss:

And 99:

(Goldschmidt will certainly be happy to see the back of Topa in the division. Like, really glad.)

To be fair, though, there seems to be something about Topa’s two-seamer that buckles hitters’ knees, no matter what velocity it’s thrown at:

While Topa can pound the bottom of the zone, he’s also not afraid to throw the pitch up, messing with a hitter’s eye level and leading to some of the freeze-pieces you see above.

Where Topa does stand out on paper is in his sweeping slider, which has a ridiculous amount of horizontal break, averaging about 15-16 inches. In that way, you can see a parallel to Sewald, whose slider also features an above-average amount of sweep, and who has said the Mariners encouraged him to focus less on getting the traditional two-plane movement in his slider and more on just getting it to sweep as much as possible. Topa didn’t get as quite much sweep on his slider in 2022 as he did in 2021, but the movement profile is there, and it fits well into the Mariners bullpen. Here, using Stacast data, is an approximation of where Topa’s slider fits in with the other sliders coming out of the Mariners’ bullpen (the starters are on there because Statcast didn’t give me a way to leave them off, so use them for reference):

Baseball Savant

There are two kinds of sliders being thrown in the Mariners bullpen: some with more rise, like those thrown by Muñoz and Sewald, and others with the more traditional two-plane drop and sweep, like Festa and Murfee. You can see Brash as the outlier there, as his slider gets some of the most dramatic horizontal movement in baseball—in fact, Brash is an outlier in all of baseball. Topa’s slider should settle right around Kirby’s for both horizontal movement and drop, and give batters another angle to contend with out of Seattle’s bullpen.

Let’s see that slider in action:

Sweepy! But this one’s my favorite:

“Possessed” does seem to be the way to describe that. Batters are Tippi Hedron in a glass telephone booth and that pitch is the bird intent on diving into it.

To acquire Topa’s services, the Mariners dealt young righty Joseph Hernández, a not-insignificant return. Hernández was on the fringe of joining Mariners’ Top-30 lists after anchoring the rotation in Modesto for the season, leading the team in most statistical categories and winning Pitcher of the Year in the Cal League. That’s a sign of how highly the team views Topa as an acquisition piece despite the injuries that have so far derailed his professional career. We know the Mariners are among the league’s best in maximizing pitchers’ arsenals; we will hope they’re also among the best at injury prevention and rehab, so they can help Topa make the most out of a right arm that hasn’t yet had its due moment in the spotlight.