At some point during those tense 18 innings on Oct. 15, just about everyone watching had to have come to the same, obvious conclusion: The Mariners and Astros have two of the very best bullpens in baseball.
Those elite arms were on full display during Game 3 of the American League Division Series. The Astros, statistically, had the game’s most valuable bullpen in 2022, and they were able to throw one more zero on the board during the 6-hour, 22-minute marathon to close out the series with a 1-0 victory at T-Mobile Park.
The Astros went on to win the World Series a few weeks later. A few months later, the Mariners enter 2023 confident they are within reach of their AL West rival in large part because of their belief in the bullpen.
The Mariners return the nucleus of that bullpen, minus veteran right-hander Erik Swanson, while adding in a couple of intriguing bounce-back candidates and waiting on one electric arm who could arrive at some point this year.
As we wrap up our position overviews before spring training, here’s a look at the options the Mariners have in the bullpen:
The Established Veterans: Paul Sewald and Diego Castillo
No, the Mariners don’t use a closer in the traditional sense. They haven’t done that for years. But Sewald has been the club’s steadiest late-inning reliever, and his leadership has been a key component of the bullpen’s success the past two seasons.
Sewald, 32, has 31 saves over the past two seasons, and he posted a career-best 2.67 ERA in 2021 with a 72/17 strikeout/walk ratio. He’s expected to be eased into spring training action after having offseason procedures on his elbow and heel.
Like many of the Mariners relievers, Castillo, 29, relied heavily on a hard slider, and he excelled in limiting hard contact, ranking in the top 5% of the league in hard-hit rate (30.6), per Baseball Savant. Castillo is scheduled to pitch for the Dominican Republic in the World Baseball Classic next month.
The Triple-Digit Threats: Andres Munoz and Matt Brash
Munoz was the biggest revelation out of the M’s bullpen in 2022. Two years removed from Tommy John surgery, and in his first full major league season, Munoz emerged as one of the most dependable relievers in baseball.
Munoz averaged 100.2 mph on his four-seam fastball, and he threw that pitch just 36% of the time. That speaks to the dominance of his slider, a pitch he threw 64% of the time — and a pitch that was virtually untouchable in the second half of the season.
Munoz struck out 96 batters in 65 innings last season, and he ranked in the top 10 among all MLB relievers in strikeout rate (38.7%) and FanGraphs WAR (1.9).
“I can’t think that he would think anything other than he’s the best reliever in baseball,” Sewald said at the end of the season. “That’s how he pitched this year. He was unbelievable. The run he had after the middle of May was pretty darn impressive.”
Munoz, 24, played the final stretch of the season with a right foot injury that required offseason surgery. He was out of his walking boot by mid-January, and the club is hopeful he’ll be good to go for opening day.
The Mariners will continue to rely on Munoz in high-leverage situations, and Brash figures to be counted on even more in those moments too.
After opening the 2022 season at the back end of the starting rotation, Brash, 24, finished the season as an elite end-of-the-game option out of the ’pen. He was perfect in three playoff appearances, allowing no hits and no walks, with four strikeouts across 3 1/3 innings.
After some discussion early in the offseason about Brash potentially shifting back to a starting role, Mariners president of baseball operations Jerry Dipoto says Brash is fully on board now as a full-time reliever.
Brash has a fastball that averaged 97 mph — and has approached triple digits — plus a devastating slider and a high-spin knuckle curveball, and he spent time this offseason at Driveline Baseball developing a cutter.
No doubt, one of the main reasons the Mariners were comfortable including Swanson in the Teoscar Hernandez trade was the presence — and potential — of Brash. It’s not a stretch to think that Brash could have the kind of breakthrough Munoz had in 2022.
The Slider Specialists: Matt Festa and Penn Murfee
Festa and Murfee are two successful draft-and-develop arms who worked their way through the Mariners minor leagues and became at least league-average relievers during their first full MLB season last year.
They achieved similar results with a similar pitch — yep, that slider — and limiting hard contact during regular middle-inning roles.
Festa, a seventh-round draft pick in 2016, struck out 64 in 54 innings, holding opposing batters to a .218 batting average and a hard-hit rate of 31.1%, which ranked among the top 6% of the league.
Murfee, a 33rd-round pick in 2018, struck out 76 in 69.1 innings, holding opposing batters to a .198 batting average and a hard-hit rate of 30.1%, which ranked among the top 3% of pitchers in the league.
You’d have to think the Mariners would be thrilled to get that same production out of both right-handers again in 2023.
The Reclamation Projects: Casey Sadler and Trevor Gott
Sadler is a familiar face returning to Seattle. Gott is a new one.
Both figure to play some role, big or small, out of the bullpen this season.
Sadler, 32, was terrific for the Mariners in 2021, posting a 0.67 ERA in 42 appearances. He missed all of the 2022 season after having shoulder surgery last March. The Mariners signed him to a minor league deal and are expected to give him every opportunity to earn back his old role.
“He was such a big part of our 2021 team, and if we get that version of Casey Sadler, with the bullpen group that we currently have, it just takes us to a different level,” Dipoto said earlier this month.
Gott, 30, is an intriguing addition, signed on a low-risk, one-year deal for $1.2 million. He had been a part-time closer for the Giants in 2020, only to spend the entire 2021 season in the minor leagues. He earned a role in the Milwaukee bullpen last season, posting a 4.14 ERA in 45 appearances.
The Wild Card: Bryce Miller
What do the Mariners have in Miller? A lot of offseason buzz, to start with. Question is, how much longer will he remain as a starter?
For a team that is in full win-now mode, and opens spring training camp with six proven starters already — with Chris Flexen probably slated for a return to a long relief role — Miller’s most likely path to the majors this season is as a reliever.
The 24-year-old right-hander pairs a fastball that sat 94-97 mph — and touched 100 — with a hard slider and a developing changeup. Sound familiar? Miller could be a midseason boost for the bullpen, much like Brash was in 2022.
The Depth
The Mariners did not employ a full-time left-hander in their bullpen last season, and they do not have a lefty projected among their top eight relievers again this season. They do have a few left-handed options in Brennan Bernardino, Gabe Speier and Tayler Saucedo, a Tahoma High School product.
Right-handers Justin Topa, J.B. Bukauskas, Isaiah Campbell, Travis Kuhn and Taylor Williams, among others, figure to get extended looks in spring training.