Smash Or Pass: Any One Of The Mariners’ Young Starting Pitchers

Texas Rangers v Seattle Mariners
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Can the Sox swing a deal for one of Seattle’s talented arms?

Welcome back to Smash or Pass, a new offseason series in which we examine various free agents and trade targets to determine whether they make sense for the Red Sox. Today, we’re taking a look at four pitchers on the Seattle Mariners, who have already engaged in trade talks with the Sox.


Who are they and where do they come from?

They are Logan Gilbert, George Kirby, Bryce Miller, and Bryan Woo, and they come from Seattle, where young, talented pitchers are apparently as plentiful as coho salmon in the Puget Sound.

Are they any good?

Collectively, they are the envy of pitching-starved clubs all over North America. Individually, they are each their own men, with their own strengths, weaknesses, and weird bathroom habits they don’t anyone to know about. For the purposes of this exercise, we’re going to break them down into two groups:

Tier 1: Logan Gilbert and George Kirby

Gilbert and Kirby (entering their age 27 and 26 seasons, respectively) have already established themselves as productive young starters with Cy Young contender upside. Gilbert beat his rotation-mate to the bigs by one season, struggling as a rookie in 2021 but displaying the big fastball and outstanding control that made him a top prospect, and finishing the year with promising peripherals, like a 3.73 FIP. Over the next two seasons, he stabilized his performance, throwing a combined 376.1 innings while striking out 363 hitters, walking just 85, and maintaining an ERA+ of 112. The only thing holding Gilbert back from jumping to the next tier of elite pitching is the relatively slower development of secondary offerings to help him miss bats. He’s working on that, though, having added a splitter last season and continuing to hone a hard slider.

Kirby doesn’t have one dominant pitch like Gilbert’s fastball, but he has something else: arguably the best control in all of baseball. He announced himself on the national stage in just 18th career appearance, when he set a Major League record by starting a game against the Washington Nationals by throwing 24 straight strikes in August 2022. In 2023, he led the league in both walks-per-nine and strikeout-to-walk ratio, as he made the All-Star team and finished eighth in the Cy Young voting. But he also made national news in not such a good way, when he complained to the press about being left in a game too long by his manager, a gripe that shocked a lot of former players and raised questions about his competitive drive.

Tier 2: Bryce Miller and Bryan Woo

Neither Miller nor Woo — both of whom have already made their MLB debuts despite only being drafted in 2021 — have established themselves as productive young starters with Cy Young contender upside yet. But it may only be a matter of time.

Miller is probably the bigger prize of the two. On the strength of a big, lively fastball and outstanding control, he flew up the minor league ladder, breaking into Seattle’s rotation this past May after making just 33 career minor league starts. He’s similar to Gilbert in that his secondary stuff needs improvement, and until he develops something to complement his heater, he’s going to get hit around from time to time. He had more than a few ugly starts last year, including 6 starts in which he gave up 5 earned runs or more. But he also held the opposition to fewer than 2 runs a whopping 13 times — that’s how good his fastball already is.

Woo underwent Tommy John surgery at the end of this college career in 2021, which delayed his entry into pro ball. But he ended up spending even less time in the minors than Miller did, getting promoted to the Majors straight from AA last June, after making just 25 career minor league starts. Scouts love his delivery and think he has a chance to develop an outstanding changeup to go with a mid-90s fastball that big league hitters hit just .207 against last year. But there’s also a general consensus that Woo was promoted far too early, before he had time to build a full repertoire of pitches. Moreover, he lacks the elite control of the other three. As a result, he was forced to lean heavily on his fastball last season and finished with a pedestrian 96 ERA+, but his Savant page gives you an indication of just how good he could be:


Tl;dr, just give me their 2023 stats.

Gilbert: 190.2 IP, 169 H, 189 K, 36 BB, 29 HR, 108 ERA+

Kirby: 190.2 IP, 179 H, 172 K, 19 BB, 22 HR, 120 ERA+

Miller: 131.1 IP, 124 H, 119 K, 26 BB, 18 HR, 93 ERA+

Woo: 87.2 IP, 75 H, 93 K, 31 BB, 13 HR, 96 ERA+

Show me a cool highlight.

Four straight minutes of a dude hitting the mitt over and over again is pure baseball ASMR. There’s a reason George Kirby has been compared to Greg Maddux.

Are they available and what would they cost?

The Mariners are open to trading from their pitching depth in order to improve their offense, and, in fact, we know that the’ve already engaged in trade talks with the Red Sox. But, so far, nothing has come together.

The Mariners, at the moment, seem to have three goals in mind:

(1) They want to win now. After enduing the longest postseason drought in North America, the Mariners finally broke through in 2022 and followed it up with another strong season in 2023, albeit one that saw them finish just outside the postseason picture. They’re led by one of the best young players in the game in Julio Rodriguez and are ready to compete right now, so giving up Major League talent solely for prospects isn’t that appealing.

But. . .

(2) They don’t want to go for it now. Mariners boss Jerry DiPoto started the offseason off with a sad trombone when he made his now infamous “.540 winning percentage” comment, essentially warning Mariners fans that they weren’t going to be major players in free agency. Unlike teams like the Rangers, Padres, Astros, or Dodgers, who appear to be trying to maximize their opportunity to win the World Series right now, DiPoto’s goal is to keep the team competitive over the long term, acknowledging that, in doing so, they’re unlikely to pay the steep prices (in either dollars or trade packages) required to acquire high-end talent on the open market. In other words, they’re not interested in rentals and likely would want to receive cost-controlled talent back in any deal they make.

And further. . .

(3) They also apparently want to cut costs. The Mariners have already made two trades this offseason. Both moves (dealing Eugenio Suarez to the Diamondbacks for Carlos Vargas and Seby Zavala, and sending former #1 overall prospect Jared Kelenic to the Atlanta Braves along with Marco Gonzalez and Evan White for Jackson Kowar and Cole Phillips) appear to have been primarily driven by the desire to trim payroll.

From the Mariners’ perspective, these three goals make for a very tight needle to thread. Hell, these goals essentially contradict each other, which is probably why talks between the two teams haven’t gotten anywhere yet. But let’s again break these guys down into their tiers to figure out what it would take to get them.

Tier 1: Gilbert and Kirby

2022 Red Sox Draft Signings
Photo by Maddie Malhotra/Boston Red Sox/Getty Images

Based purely on value, any package for either Gilbert or Kirby would likely need to be centered around one of the four most valuable assets in the entire Red Sox organization: Triston Casas, Marcelo Mayer, Roman Anthony, or Kyle Teel.

Casas would actually be a pretty good fit for the Mariners. As Sox fans know, he wasn’t just one of the best young hitters in baseball in the second half of last season, he was one of the best hitters of any age; he would represent a big, cost-controlled improvement over Seattle’s incumbent first baseman Ty France. But the Sox are counting on Casas anchoring their lineup for years to come. And while swapping Casas for Gilbert or Kirby might make the Sox more balanced, it wouldn’t make them any better.

That leaves the prospects. I believe the Sox absolutely would — and should — be happy to part with one of the big three to net either Gilbert or Kirby. Of course, the Mariners would need more than one top prospect in return. We’d probably be looking at a package headlined by one of Mayer/Anthony/Teel and filled out by three more of the Sox top 20 prospects. It hurts to give up that much prospect depth in one deal, but when the return is a young, cheap potential Cy Young contender, you don’t hesitate to pull the trigger.

Unfortunately, while this deal would help the Mariners achieve their second and third goals, it wouldn’t do anything for their first. In fact, not only would this deal do nothing to make the 2024 Mariners better, it would make them worse. If Jerry DiPoto is at all interested in freely moving about the Seattle area without having to wear a fake mustache, it’s hard to see him pulling the trigger here.

Tier 2: Miller and Woo

Boston Red Sox v Baltimore Orioles
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Either Miller or Woo could likely be had without giving up one of the big three. But given the Mariners’ desire to win now, a package that doesn’t include any MLB-ready talent probably wouldn’t get it done, either. Luckily, one of the Mariners’ weakest spots on the roster, the corner outfield positions, happens to be an area where the Red Sox have something of a surplus.

We can rule out Masataka Yoshida as a trade fit thanks to the Mariners’ desire to cut costs. But Jarren Duran, Ceddanne Rafaela, and Wilyer Abreu are all young, cheap outfielders with upside. In the case of Duran and Rafaela, we’re talking about serious upside.

Duran performed at a near-All-Star level for much of last season, while Rafaela is, according to some evaluators, a top-50 prospect in all of baseball who has nothing left to prove in AAA. But both players also have some major points of concern. Duran’s offensive production was buoyed by a ridiculous .381 BABIP last season. Someone as fast as Jarren Duran would be expected to have a higher than average BABIP — but not only would that .381 mark have led the league last year if Duran had qualified, it would have been the fourth-highest BABIP of the last five non-COVID-shortened seasons combined. That’s plainly unsustainable, and Duran’s due for a regression.

Rafaela, meanwhile, is one of he most divisive prospects in baseball. He’s a wizard with the glove who has put up outstanding offensive numbers at every minor league stop he’s made. But he’s also a very undisciplined free-swinger and many evaluators think his approach simply will not work at the Major League level at all. So whether either Duran or Rafela could headline a deal for Woo or Miller would likely depend on Seattle’s own internal evaluations of the return, and it’s really hard to guess what those evaluations say from the outside.

From the Red Sox perspective, while I suspect Craig Breslow wouldn’t hesitate to deal someone like Duran for Woo or Miller, we have to note that neither pitcher is, as of now, what the Sox are supposedly looking for this offseason. The Sox want two top of the rotation pitchers. Woo and Miller are extremely talented, but that’s not what they are yet. In fact, no one would really be surprised if guys like Kutter Crawford, Nick Pivetta, or Tanner Houck all ended up out-pitching either one in 2024.

Smash Or Pass?

I wouldn’t hesitate to pull the trigger on either (A) a package headlined by one of Mayer, Anthony, or Teel for Gilbert or Kirby, or (B) a package headlined by one of the Red Sox young outfielders for Woo or Miller. But, unfortunately, it’s not clear that either one of those deals gets done. Meanwhile, I would pass on giving up Casas — he has the potential to be the biggest fan-favorite in Boston since David Ortiz hung up his chain.

Unfortunately, while both the Sox and Mariners appear willing to deal, this might be a situation where the pieces just don’t fit.

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