AL Division Series Preview: Mariners (90-72) at Astros (106-56)

After their miraculous victory over the Blue Jays on Saturday, the Mariners advanced into the Division Series to face the Astros, the best team in the American League. They’re a well-known opponent, even if the Mariners look a lot different than the last time they faced Houston. With nearly two-thirds of their regular season games scheduled for the first half of the season and the season series wrapped up by July, these two teams might not be as familiar with each other as you’d expect for two division rivals. Most importantly, the Astros haven’t faced Luis Castillo who is lined up to start potentially two games this series (more on that below).

While there are positives to be gleaned from the improvements the Mariners have made during the second half of the season, make no mistake, the Astros are the heavy favorites to advance to their sixth consecutive AL Championship Series. Not only do they have to contend with an extremely formidable roster, the Mariners will also have to get over the mystique of playing in Minute Maid Park. Since 2017, they’re 19-37 in Houston and have won just one single series in the last four seasons there. There’s also the lingering “bad blood” between these two clubs that’s been brewing since Dylan Moore launched a game-winning grand slam against them last year, boiling over again in June with a benches-clearing incident. There will be no shortage of off-field distractions ready to derail the Mariners. A clear-eyed focus on playing each game as it comes will be paramount if they want to try and squeak by this juggernaut. —JM

In the new playoffs format debuting this year, the top two seeds get a bye into the best-of-five Division Series, so the Mariners will face a well-rested Houston Astros in Texas tomorrow. The Astros have made the playoffs every year since 2017, when they won the only championship title in the team’s history. They’ve been to the World Series three times in that era, and have won 100 games four out of the past six years. This record of success is, of course, tainted by the famous cheating scandal that calls into question the validity of Houston’s 2017 and 2018 victories.

In another banner year this year, the Astros won the AL West with 106 wins, sitting 16 games above the 2nd-place Mariners. Houston won the season series 12 games to 7, sweeping Seattle twice (at home and away). Headlining several of those victories has been the pitching of Justin Verlander, who has continued his dominance against the M’s in an age-39 season where he’s the frontrunner to win the AL Cy Young. On the other side, Mariners infielder Abraham Toro has come up clutch several times against his former team this year despite his generally disappointing season.

While starting pitching has been the Astros’ strength this season, and is their key to unlocking postseason success, the offense has standout stars as well, and the team has been lucky in terms of player health. Aside from three players whose seasons ended months ago (left fielder Michael Brantley, catcher Jason Castro, pitcher Josh James), the team comes into the postseason healthy, with no players on the shorter-term injured lists. The Astros are favored to win this series, with both FanGraphs and FiveThirtyEight giving them the highest likelihood to be the American League representative to the World Series. –LFS

The Astros lineup includes familiar foes and valuable young players, posting a team wRC+ of 112, but with weaknesses at first base, center field, and catcher (incidentally the three positions at which MLB’s Mike Petriello gives the Mariners the edge). Designated hitter/left fielder Yordan Álvarez boasts a fearsome 185 wRC+ for the regular season; he’s hit five home runs against the Mariners this year and will likely place in the top three-to-five in MVP votes. With his last fourteen home runs coming as solo shots, Álvarez will be looking to hit big with men aboard this week. Longtime nemesis José Altuve matches Álvarez with 6.6 fWAR, and is second on the team in both wRC+ (with 164) and home runs against the M’s (with four). Notably, he also has the second most postseason home runs in MLB history. Houston’s other two players in the starting lineup with a wRC+ greater than 125 are third baseman Alex Bregman (136) and right fielder Kyle Tucker (129).

Rookie Jeremy Peña began the year in quick competition with Julio Rodríguez for rookie of the year, but cratered midsummer and is no longer in the ROY conversation (which Julio has locked up at this point). Since August 30th, Peña’s numbers have turned back around, and Astros fans are hoping he’ll be able to contribute in October and return to his early-season form going forward. Eight players on Houston’s likely postseason roster have multiple multi-hit games against the Mariners this year: Peña, Tucker, Bregman, Altuve, Álvarez, as well as Yuli Gurriel, Aledmys Díaz, and Martín Maldonado. —LSF

Probable Pitchers

Updated Stuff+ Explainer

Game 1

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Because the Astros spent the last week resting and preparing for this second-round matchup, they have the benefit of setting their rotation however they like. Some kind of clubhouse illness has delayed the announcement of the full rotation for Houston, but we do know they’ll lead with Justin Verlander. After missing the last two trips through October after his Tommy John surgery in 2020, he’s back to lead the team through the postseason again. It will be his 31st postseason start and the seventh time he’s faced the Mariners this season alone. The results speak for themselves — a career-best 1.75 ERA and 2.49 FIP have him as the favorite to win the AL Cy Young award — but his peripherals aren’t as shiny. His strikeout rate is the lowest it’s been since 2017, the same year he was traded to Houston from Detroit. He’s found much of his success this year by curtailing nearly all hard contact against him. Fantastic command of his fastball and breaking pitches make him nearly impossible to square up and he allowed a career-low 12 home runs this season.

Lined up to start a potential Game 3 of the Wild Card series in Toronto, Logan Gilbert will instead lead the Mariners pitching staff in the Division series. He faced the Astros four times during the regular season, holding them to just seven runs in 25 innings with 22 strikeouts. He’s also extremely well rested, having pitched last nearly two weeks ago.

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Game 2

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Things could change if the illness spreading through the Astros clubhouse lingers, but I’d expect Framber Valdez to take the mound in Game 2. He famously broke the major league record for consecutive quality starts this year, eventually hitting 25 in a row. That wasn’t the only historic record he approached either; his 4.16 ground-ball-to-fly-ball ratio was the second highest for any qualified starter since batted ball tracking began in 2002. A new cutter has helped him increase his effectiveness against left-handed batters while his sinker and curveball continue to cause everyone to pound the ball into the ground. He faced the Mariners twice during the regular season, allowing three runs in both outings.

Due to the weird off day between Games 1 and 2, Luis Castillo would be able to make the start on Thursday with an extra day of rest. He was acquired in the middle of Seattle’s final series against Houston in late-July but didn’t get the opportunity to face them. In his Wild Card start in Toronto, Castillo’s entire repertoire enjoyed a hefty velocity bump, and his sinker carried an additional two inches of arm-side run on the night. We’ll see if he can carry those improvements into his start in Houston.

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Game 3

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Update: The Astros announced on Tuesday morning that McCullers Jr. would start Game 3. That means Javier would likely line up to start Game 4, though that hasn’t been formally announced.

With Verlander and Valdez the easy picks to top the Astros rotation, picking a starter for Game 3 gets a little tricky. Lance McCullers Jr. recently returned from the forearm injury he picked up during the postseason last year, and made eight solid starts for the Astros down the stretch. Based on track record and playoff experience, he’s the obvious candidate, but Cristian Javier had a much more impressive season and would probably be just as good a pick. He enjoyed a breakout year behind an extremely impressive fastball and a pair of excellent breaking balls. His repertoire didn’t just earn swings and misses, it also was nearly impossible to barrel up. His .308 expected wOBA on contact sat in the 96th percentile in the majors and batters managed to put hard contact in play on just a third of their batted balls against him.

The Mariners face a difficult decision for Game 3. Robbie Ray would be lined up to make this start but his performance in Toronto was ugly and the Astros really knocked him around this year; in three starts against Houston, he allowed 14 runs and 23 hits in 10.2 innings. The alternative would be to start George Kirby, a pretty significant change after his ninth inning appearance in Game 2 of the Wild Card series. He faced the Astros once during the regular season, holding them to two runs in four innings while striking out seven. I could see a situation where, if the Mariners win one game in Houston, they’d run Ray out on a short leash like they did in Toronto. If they’re on the brink of elimination, then Kirby is probably a better bet. I could also see them simply committing to use Kirby in the rotation and pushing Ray into the bullpen with his only role to face Alvarez or Tucker in their first high-leverage at-bat. There have been some who have suggested starting Marco Gonzales or even Chris Flexen at some point during this series and I have one thing to say about that: if you’re choosing to start one of those guys against the Astros, you’ve seriously overthought your process.

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Games 4 & 5

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Things could get really weird in Games 4 and 5 depending on how the first three games go. Because of the wonky schedule, the Game 1 starters would be able to make the start in Game 4 on regular rest, though the Game 2 starters wouldn’t be able to do the same in Game 5. That means the teams could use a fourth starter if they don’t feel comfortable running a pitcher out on short rest. The Astros have the depth to go four deep if needed, and keeping Verlander fresh and healthy for a deep postseason run has to be a priority for them. I expect them to use McCullers Jr. or Javier in Game 4 (whichever one doesn’t start Game 3) and then start Verlander in a potentially decisive Game 5 on an extra day of rest. Of course, everything is on the table if they’re facing elimination in either of these games.

I think the Mariners are a little more liable to use one of their starters on short rest, potentially lining up Gilbert in Game 4 on regular rest and Castillo in Game 5. The other option would be to use Kirby or Ray (whichever doesn’t start Game 3) in Game 4 and then use Gilbert or Castillo in Game 5. These decisions will be up in the air depending on how the beginning of the series goes.