AL Division Series Preview: Houston Astros vs. Seattle Mariners

© Troy Taormina-USA TODAY Sports

When the American League Division Series begins on Tuesday, the Seattle Mariners will take on the Houston Astros as the ultimate underdogs. The Mariners are in the midst of their first postseason run in over 20 years, while the Astros have made their way to the ALCS in each of the past six seasons. No matter how you slice it, the Astros are the overwhelming favorites.

In fact, this might be the most winnable ALDS matchup the Astros have had over their seven-year run. Never before has the gulf between the Astros and their opponent been this wide:

Houston Astros ALDS Opponents Since 2017
Year Astros Record Opponents Record Difference Astros Pythag. Record Opponents Pythag. Record Difference
2017 101-61 93-69 8 99-63 93-69 6
2018 103-59 91-71 12 109-53 98-64 11
2019 107-55 96-66 11 107-55 93-69 14
2020 29-31 36-24 -7 30-30 35-25 -5
2021 95-67 93-69 2 101-61 97-65 4
2022 106-56 90-72 16 106-56 89-73 17

In theory, that means an upset is unlikely. But this isn’t the first time the Mariners have heard that. On Opening Day, their playoff odds stood at 22.8%; at the lowest point of their season, those odds dropped to 5.1%. When they finally did make the postseason, they were still the underdogs, forced to face Alek Manoah and Kevin Gausman (not to mention the Blue Jays’ fearsome offense) in a three-game set on the road. Yet here they are, one of the four AL teams still standing.

It brings to mind the story of David and Goliath. The question is, are the Astros really Goliath? They’ve certainly got the big and strong thing going for them, and perhaps a bit of villainy, too. But there’s something else that makes for a Goliath, a necessary trait that often gets overlooked: a fatal flaw. A Goliath needs a clear weakness the hero can use to their own advantage, be it a poorly designed thermal exhaust port, the one ring or even the villain’s confidence that no such vulnerability exists.

So do the Astros have a fatal flaw the Mariners can exploit? Or will they send the Mariners packing, proving they were the favorites for a reason? Let’s take a look at how the two teams match up.

Astros Run Prevention vs. Mariners Run Production

When it comes to run prevention, no AL team comes close to the Houston Astros. In fact, no AL team from the past 50 years can touch them. Astros opponents scored only 518 runs in 2022, an average of 3.2 per game. That’s the lowest number for an AL team in a full season since 1969. That accomplishment can in part be attributed to the decreased run environment around the league, but it still speaks volumes about the pitching staff and defense Houston has put together.

The Astros led the AL with 31 Outs Above Average this season, 10 more than the next-best Yankees; they ranked third with 67 DRS. While plenty of the credit for those excellent defensive metrics goes to Jose Siri, who was traded to Tampa Bay mid-season, Houston still has an elite defense without him. Chas McCormick has been an elite protector in center field, and when paired with Kyle Tucker in right, those two can cover enough ground to make up for the shortcomings of either Yordan Alvarez or Trey Mancini in left.

Meanwhile, on the infield, Jeremy Peña is a future Gold Glove winner at shortstop, and both Alex Bregman and Jose Altuve are solid on either side of him. The defensive metrics don’t look too kindly on Yuli Gurriel at first base or Martín Maldonado at catcher, but it’s clear the Astros believe in their guys. And for what it’s worth, Gurriel is only one season removed from winning a Gold Glove, while Maldonado’s performance behind the dish gets rave reviews from his pitchers and his coaching staff. No matter how you feel about their defense, neither can really be called a fatal flaw:

Active Astros OAA (min. 200 innings)
Player RAA OAA
Jeremy Peña (SS) 5 7
Jake Meyers (CF) 6 7
Alex Bregman (3B) 4 5
Chas McCormick (CF) 5 5
Kyle Tucker (RF) 3 3
Jose Altuve (2B) 1 2
Chas McCormick (LF) 1 1
Mauricio Dubón (CF) 0 -1
Yordan Alvarez (LF) -5 -5
Yuli Gurriel (1B) -7 -9

If there’s good news for the Mariners here, it’s that their offense is built to thrive against even the best defensive alignment. Their 9.7% walk rate ranked second in the AL this season, and they were fifth in home runs with 197. Even better, they ranked second with 100 homers on the road, perhaps a more telling number since T-Mobile Park isn’t exactly a hitter-friendly environment. Four hitters in the starting lineup – Julio Rodríguez, Eugenio Suárez, Cal Raleigh, and Ty France – hit at least 20 bombs this season, while three – Suárez, Carlos Santana, and J.P. Crawford finished with a walk rate over 10%. Accordingly, the Mariners do not rely on a high BABIP to generate offense. Their .272 BABIP ranked second-last in the AL, and their .278 BABIP on the road was third lowest. Thus, they can still reach base and drive in runs regardless of who is in the field — that is, as long as the Astros pitching staff doesn’t completely shut them out.

Because as good as Houston’s defense has been, the real stars of the run prevention show are the pitchers. The starting rotation is spine-chilling, with the collective numbers of a Cy Young. That’s hardly even an exaggeration – take a look at the Astros starting pitchers compared to 2021 AL Cy Young winner (and current Mariner) Robbie Ray:

The Astros Rotation Could Win a Cy Young
Unit/Player ERA FIP K/BB HR/9 IP/start
2022 Astros Rotation 2.95 3.41 3.51 0.93 5.86
2021 Robbie Ray 2.84 3.69 4.77 1.54 6.04

The Astros rotation is so good that it’s hard to know for sure who will start in the ALDS. After finishing his first full season in three years with a 1.75 ERA and 2.49 FIP in 28 starts, Justin Verlander is a lock for Game 1. After him, though, it gets a little more complicated, with Dusty Baker not revealing the club’s Game 2 starter; there’s an illness circulating in the clubhouse, and they need to see how everyone is feeling.

Illness aside, for most of the year, Framber Valdez would have seemed like the obvious choice – he made 25 consecutive quality starts from April to September – but he faltered late in the season, pitching two poor games in a row against Baltimore and Tampa Bay. With that in mind (and assuming everyone feels ok), Baker might prefer to play the hot hand, Cristian Javier. Since early September, Javier has gone 26.1 IP without allowing a run, striking out 31 batters along the way. The Astros have won each of his last six starts. Although Valdez was Mr. Reliable for most of the year, Javier might have replaced him over the past month. He has gone at least five innings while allowing three or fewer runs in his last 13 starts.

For Game 4, Baker will presumably tap Lance McCullers Jr., who started Game 1 of the ALDS for the Astros just last season. In eight starts since returning from the IL, McCullers has a 2.27 ERA and 3.49 FIP in 47.2 IP. He needs to give up fewer free passes (4.15 BB/9), and he could benefit from throwing more first-pitch strikes, but he showed signs of progress on both fronts in his final start of the regular season and has earned a postseason start over either of José Urquidy and Luis Garcia.

Urquidy and Garcia should, however, expect to get some work out of the Astros bullpen. The relievers have been every bit as impressive as the starters in Houston, posting a 2.80 ERA and 3.05 FIP in 495.1 IP. It’s worth mentioning how low that innings pitched total is – it’s the lowest in the league by almost 50 innings – but that is merely a reflection of how good the starting pitching has been. The Astros have the deepest bullpen in the AL, and if Baker needs more innings from his relievers, it would hardly pose an issue. Ryan Pressly, Bryan Abreu, Rafael Montero, and Ryne Stanek have been dominant this season, while Héctor Neris, Will Smith, and Phil Maton make a terrific second line of defense. Top prospect Hunter Brown excelled in his big league cup of coffee out of the bullpen, and Urquidy and Garcia will fortify an already formidable group. Most postseason teams choose to rely heavily on their best three or four relievers, which can be a risky move. Houston won’t have to worry about that at all – there isn’t a weakness in sight here:

Houston Astros Bullpen Options
Name G IP K/9 BB/9 HR/9 ERA FIP xFIP
Hector Neris 70 65.1 10.88 2.34 0.41 3.72 2.35 3.29
Rafael Montero 71 68.1 9.61 3.03 0.40 2.37 2.64 3.22
Bryan Abreu 55 60.1 13.13 3.88 0.30 1.94 2.12 2.69
Ryan Pressly 50 48.1 12.10 2.42 0.74 2.98 2.31 2.21
Ryne Stanek 59 54.2 10.21 5.10 0.33 1.15 3.02 3.95
Will Smith 24 22.0 9.82 1.64 0.82 3.27 2.66 3.09
Phil Maton 67 65.2 10.01 3.29 1.37 3.84 4.33 3.82
Hunter Brown 7 20.1 9.74 3.10 0.00 0.89 1.98 2.78
Luis Garcia 28 157.1 8.98 2.69 1.32 3.72 3.93 3.82
Jose Urquidy 28 162.1 7.37 2.00 1.50 3.88 4.43 4.28

That isn’t to say Houston’s pitching staff will walk all over the Mariners. The top of Seattle’s order would give any pitcher pause. The rookie phenom Rodríguez, who can hit just about any pitch he sees for power or average, leads off, and he’s followed by three solid power bats in France, Suárez, and Raleigh, giving the young superstar ample protection in the lineup. The veteran Mitch Haniger has been hitting the ball pretty well, too, since his return from a long stint on the injured list.

Since the start of September, Rodríguez has been playing on another level, and the rest of his teammates have followed suit. Rodríguez hit .394 with a 246 wRC+ in September and October, and Raleigh put up some monstrous numbers in that span as well (eight home runs, 171 wRC+). Suárez, meanwhile, continued raking (six home runs, 139 wRC+), and several others busted out of their midsummer slumps, including France, Santana, and Crawford.

The Mariners had excellent plate discipline all season long, and it only improved as the year went on. From September 1 to the end of the season, they walked at a league-leading 10.8% clip. In that time, they swung at fewer pitches outside the zone than any other team in baseball and had the highest first-pitch strike rate, too. As fate would have it, this is one of the few areas where the Astros pitching staff hasn’t excelled. Their 2.85 BB/9 in 2022 ranked seventh in the AL, as did their swing rate on pitches outside the zone. Their first-pitch strike rate was third-lowest in the league. It’s not quite a weakness for Houston, per se – they still walk fewer batters than the average team – but it could be an entry point for the Mariners. If Seattle can continue earning first pitch strikes and avoiding pitches outside the strike zone, it could be their best way to get past Houston’s stronghold. This approach won’t just lead to more walks, but more hitters’ counts too, putting the Mariners in a better position to succeed.

Mariners Run Prevention vs. Astros Run Production

While run prevention is what they do best, the Houston Astros are pretty fantastic when it comes to scoring runs, too. They finished the regular season third in the American League in runs scored and wRC+, trailing only the Yankees and Blue Jays, two offensive powerhouses.

Four Silver Slugger candidates lead the Astros offense, and you’d be hard-pressed to find a better core four in any other lineup:

Houston Astros Top Offensive Performers
Player HR AVG OBP SLG wRC+
Jose Altuve 28 .300 .387 .533 164
Yordan Alvarez 37 .306 .406 .613 185
Alex Bregman 23 .259 .366 .454 136
Kyle Tucker 30 .257 .330 .478 129

McCormick is also putting together a solid season with excellent offensive numbers for a center fielder, and Peña seems to have finally found his groove after a bad slump during the summer months. The rest of the lineup leaves something to be desired, with Gurriel still playing every day despite his poor performance, Mancini floundering since he left Baltimore, and neither Maldonado nor Christian Vázquez hitting a lick. Once again, however, it’s hard to call this a weakness when the top of the lineup more than makes up for the bottom’s shortcomings.

It won’t be easy keeping this offense quiet, but the Mariners do have some pretty talented pitchers to turn to. Luis Castillo started Friday in the Mariners’ Wild Card Series Game 1 victory over the Blue Jays, so he won’t be ready to go right away in Houston. Instead, Scott Servais will give Logan Gilbert the ball. While some Mariners fans might be upset that Castillo can’t start Game 1, Gilbert is no mere consolation prize. He broke out in 2022, posting a 3.20 ERA and 3.46 FIP in 32 games. He’s been especially good of late, making six starts in September with a 2.00 ERA and 2.39 FIP. In his final outing of the regular season, he went eight innings against the Athletics, giving up just one run on three hits.

Most importantly, Gilbert seems especially well-suited to succeed against Houston. In four starts opposite the Astros this season, Gilbert has a 2.52 ERA with 22 strikeouts and just three walks:

Logan Gilbert Against the Houston Astros in 2022
Start IP H ER K BB HR
5/28 7.0 4 0 5 0 0
06/08 6.0 7 3 3 3 0
7/23 6.0 5 2 8 1 0
7/28 6.0 5 2 6 2 1

To see why Gilbert might be such a good foil for the Astros, we can take a look at how he matches up against right and left-handed batters. Despite being right-handed himself, he has had much more success against lefties in his career. In his first professional season, across three minor league levels, Gilbert posted small but noticeable reverse platoon splits. Nothing shocking, but noteworthy numbers nonetheless:

Logan Gilbert 2019 MilB Platoon Splits
K/BB OPS
vs. LHH 5.23 .573
vs. RHH 4.85 .517

In 2021, Gilbert continued to demonstrate noticeable reverse platoon splits, this time at the big league level. He allowed far more home runs and extra-base hits to right-handers, and his ISO against righties was almost 100 points higher than it was against lefties. Again, it was nothing crazy – and it certainly could have been a small sample fluke – but whatever the reason, it was apparent Gilbert was seeing better results against left-handed batters:

Logan Gilbert Platoon Splits 2021
K/9 BB/9 K/BB HR/9 ISO wOBA FIP xFIP
vs. LHH 9.2 2.8 3.4 0.8 .132 .285 3.21 4.00
vs. RHH 10.0 1.6 6.5 1.7 .227 .322 4.19 4.35

Subsequently, this current season, Gilbert’s platoon splits were even more pronounced. He maintained a high strikeout rate against lefties even though his strikeout rate against righties dropped precipitously, and he continued to limit home runs and XBH against left-handed batters:

Logan Gilbert Platoon Splits 2022
K/9 BB/9 K/BB HR/9 ISO wOBA FIP xFIP
vs. LHH 9.6 3.0 3.2 0.5 .111 .256 2.71 3.44
vs. RHH 7.4 1.9 4.0 1.3 .178 .334 4.14 4.08

The secret to his success seems to be his changeup, which he throws almost exclusively to lefties, and which has been his most dominant offering on a pitch-by-pitch basis this season (per Sports Info Solutions runs above average). He is a three-pitch pitcher against righties, but a four-pitch pitcher against left-handers, and that seems to be working in his favor.

It’s still too early in his career to say for sure that Gilbert can maintain reverse platoon splits, but it’s something to consider, especially when he’s facing the Astros. The Astros are the team of Alvarez and Tucker, two of the best left-handed hitters in the game. Typically, that duo annihilates opposite-handed pitching, but Gilbert’s unique abilities against left-handed hitters might help him stand his ground. They certainly won’t make it easy for him (especially Alvarez, who has hit changeups quite well this season), but Gilbert should have a better chance against these two than most other right-handed pitchers.

If he can hold his own against Alvarez and Tucker, he’ll have a much easier time dealing with the rest of the offense. A sizable chunk of the Astros’ lineup (pretty much anyone outside the core four) has struggled against right-handed pitching this year, including Peña, McCormick, Maldonado, and Gurriel. Thus, overall, the team is noticeably worse against right-handed pitchers. They’re still good of course (this is the Astros we’re talking about), but when a righty is on the mound, less than half the lineup is doing nearly all the heavy lifting. With this is mind, Gilbert might represent the best of both worlds for the Mariners. His right arm can neutralize the bottom of the order, while his unique platoon splits will come in handy against Alvarez and Tucker.

After Gilbert, Castillo seems a safe bet to return to the mound for Game 2. As another right-handed pitcher, he should give the M’s a solid chance to quiet the Astros offense. In his excellent start in Toronto, he went 7.1 scoreless innings, striking out five and walking none. The Blue Jays have a top-tier offense, but their lineup is entirely right-handed, so the Astros will pose a greater challenge for Castillo.

If I had my druthers, rookie phenom George Kirby would get the ball in Game 3. Kirby closed out the game on Saturday, sending the Mariners to the ALDS and making his first big league relief appearance in the process. But Kirby’s home is in the starting rotation. In 25 starts, he put up a 3.39 ERA, 2.99 FIP, and 3.0 WAR. His 6.05 K/BB ranked fifth in the American League (min. 100 IP). Similar to Gilbert, he has reverse platoon splits this season, having held left-handed batters to a .245 wOBA and 2.33 FIP. That’s a tiny sample size of course – far smaller than Gilbert’s – but it’s something to keep an eye on. And while he hasn’t had quite as much experience facing the Astros, he did strike out seven batters in his only start against Houston this season.

That trio of starting pitchers gives Seattle a legitimate chance to compete in the first three games of the ALDS. Facing off against the likes of Alvarez, Tucker, Altuve, and Bregman will no doubt be a challenge, but Gilbert, Castillo, and Kirby can all hold down the fort. But if the Mariners do reach Game 4, they’re going to run into a problem. Assuming Kirby starts Game 3, Ray is the most likely choice to take the hill, but he isn’t exactly the best option against a team like the Astros. Ray, of course, is left-handed, and he has been hit around by right-handed batters all season — look no further than Saturday in Toronto. The Astros, in particular, have had his number, tagging him for 14 runs in 10.2 innings of work. It doesn’t help that Ray’s go-to secondary pitch is a slider, and there’s no pitch Astros hitters like better. Other M’s pitchers use a slider too, but none rely on the pitch nearly as heavily as Ray does.

If he runs into trouble, Servais would be smart to keep Ray on a very short leash. As long as he doesn’t lean too heavily on the bullpen during the first three games, that should be possible. Seattle has a solid – and very righty-heavy – bullpen, with arms like Paul Sewald, Andrés Muñoz, Erik Swanson, Matt Brash, and Penn Murfee to throw Houston’s way:

Seattle Mariners Bullpen Options
Name G IP K/9 BB/9 HR/9 ERA FIP xFIP
Andrés Muñoz 64 65.0 13.29 2.08 0.69 2.49 2.04 2.04
Erik Swanson 56 51.2 12.02 1.74 0.52 1.74 1.84 2.69
Matt Brash 34 30.2 12.62 4.70 0.00 2.35 1.97 2.99
Penn Murfee 63 67.1 9.89 2.27 0.94 3.07 3.11 3.56
Paul Sewald 65 64.0 10.13 2.39 1.41 2.67 3.88 3.58
Diego Castillo 59 54.1 8.78 3.64 0.83 3.64 3.68 3.85
Matthew Festa 53 54.0 10.67 3.00 1.67 4.17 4.26 3.47

In an ideal world, the Mariners would also be throwing plenty of cutters the Astros’ way. The Astros have been worth 15.4 runs below average against cutters this season, per SIS. That ranks 27th in baseball and dead last in the AL. Alvarez, Tucker, and Bregman have all been stymied by the cut fastball. The only problem, of course, is that no one on the Mariners postseason roster – at least as it stands right now – throws the pitch. This could have been Houston’s fatal flaw, but Seattle won’t be able to take advantage.

And that brings us right back to David and Goliath, and the issue therein. The Astros don’t seem to have a mortal weakness – or at least, not one the Mariners can exploit. They’re just too powerful. But then, that’s probably exactly what the Israelites said about Goliath back in the day. By facing Goliath in spite of the odds, David gave himself the chance to win. He gave himself the chance to discover a weakness that others could not see.

Now it’s the Mariners’ turn to face the beast. They too will compete and give themselves the chance to win. Whether or not they come out alive remains to be seen.





Leo is a writer for FanGraphs and an editor for Just Baseball. His work has also been featured at Baseball Prospectus, Pitcher List, and SB Nation. You can follow him on Twitter @morgenstenmlb.

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Logan Davismember
3 months ago

I’m not sure why the Mariners would go to Ray here. With off days on Wednesday and Friday, wouldn’t Gilbert be starting game 4 on ~normal rest (4 days)? I suppose then you have the question of Game 5, and whether Castillo can go again on only 3 days’ rest.