SB Nation • 15 min read

Series Preview/Know Your Foe: Seattle Mariners @ Houston Astros

Houston swept the 1st series of its final six-game homestand. Now, on to the Mariners. What a way to close out the regular season home schedule.

Mariners Standings:

84-69 (Tied for 1st in the AL West)
Road Record: 36-42 (Astros Home Record: 46-32)
Record vs. AL West: 31-18 (Astros vs AL West: 22-21)
Last 10: 9-1 [WWWWWWWWLW] (HOU: 6-4 [LLWLWWLWWW])
Record since last match-up: 31-23 (HOU record: 27-27)
2025 Record vs. Houston: 5-5 (Won @ SEA 2-1 4/7-4/9; Lost 1-3 @ HOU 5/22-5/25; Won 2-1 @ SEA 7/18-7/20)

All-Time Record vs. Houston: 94-135
Playoff Record: 0-3 (2022 ALDS)

Mariners Since the Last Meeting: A lot of ying and yang with the Mariners. Until this past week, they’ve been just on the Astros’ heels, getting close, but just unable to overtake the scuffling Astros. A big reason is that Seattle couldn’t win on the road. They’ve definitely been taking care of business at home, and as of late, have been playing

a fairly friendly overall schedule, as seen by their recent 10-game win streak to vault into a tie for the AL West lead. As has been the case for 2025, the Big Dumper is leading the way, making the push to get 60 dingers and perhaps claim the MVP away from Aaron Judge. Also, the ballyhooed starting rotation is starting to find the range, which could make Seattle a dangerous foe for any playoff matchup. Likely the final disposition on potential playoff seeding/matchups won’t get settled until the very end of the season.

Mariners Leaders

Offense: [NOTE: Stat leaders based eligibility for batting title and who is currently on the roster, unless otherwise noted]

HR: C Cal Raleigh (56)
RBI: C Cal Raleigh (118)
BA: CF Julio Rodriguez (.271)
OPS: C Cal Raleigh (.951)

Pitching: [NOTE: Stat leaders based on eligibility for ERA title and who is currently on the roster, unless otherwise noted]

ERA: Bryan Woo (3.02)
Wins: Bryan Woo (14)
Saves: Andres Munoz (35)
WHIP: Bryan Woo (.94)

Projected Pitching Matchups (SUBJECT TO CHANGE)

Friday, September 19 @ 7:15 CDT: Bryan Woo (14-7, 3.02 ERA) vs. Hunter Brown (12-7, 2.27 ERA)
Saturday, September 20 @ 6:10 CDT: George Kirby (9-7, 4.46 ERA) vs. Framber Valdez (12-10, 3.59 ERA)
Sunday, September 21 @ 6:00 CDT: Logan Gilbert (5-6, 3.53 ERA) vs Jason Alexander (4-1, 4.04 ERA)

Mariners Field Position Starters (SUBJECT TO CHANGE) (BA/OBP/SLG)

C: Cal Raleigh (.247/.359/.585)
1B: Josh Naylor (.276/.319/.459) [Information based on his time since trade from Arizona]
2B: Cole Young (.214 /.305/.312)
3B: Eugenio Suarez (.182/.253/.406) [Information based on his time since trade from Arizona]
SS: J.P. Crawford (.264/.352/.369)
LF: Randy Arozarena (.239/.339/.436)
CF: Julio Rodriguez (.269/.321/.475)
RF: Victor Robles (.264/.284/.330)
DH: Jorge Polanco (.266/.327/.492)

Mariners Offense: It will be interesting to see what happens in the MVP race between Aaron Judge and Big Dumper. Judge is Judge, but Raleigh is putting up numbers baseball has never seen from a full-time catcher. With nine games left, he might just get to 60, if not exceed it. Yet, this is more than a one-Dumper show. Other bats are driving the Mariners towards their second postseason berth since 2001. The Mariners rank in the top half in MLB offensive numbers (10th in runs, 11th in OBP and SLG). Boosting the Big Dumper’s efforts are outfielders Julio Rodriguez and Randy Arozarena, both of whom have a history of tormenting the Astros. DH Jorge Polanco can also offer some pain with the lumber, with an OPS over .800. Since the trade deadline, 1B Josh Naylor has offered some positive offensive contributions, whereas Eugenio Suarez has not. Still, Suarez, when he faced Houston before the trade deadline, did some damage to the Houston rotation. Seattle’s running game (4th in stolen bases) can also put pressure on the Houston defense.

Mariners Pitching/Defense: Perhaps the long-dormant pitching staff is finally recapturing its lost throwing abilities. Their overall ERA ranking is 13th, with their BAA at 14th in MLB. Their WHIP is up to 8th, which is starting to get more in-line with the promise of the rotation. Bryan Woo has been the most consistent hurler for the staff, but some of other starters are getting back to full strength, like George Kirby. When the starters are on, you could argue that Seattle has 5 top-of-the-rotation guys, which is a rather nice thing to have coming into postseason-level play. The bullpen has been solid, ranking 10th in ERA. Munoz among the league leaders in saves with 35. However, the bullpen hasn’t been completely nails, as they do have 25 blown saves to their record. Seattle’s defense is a bit mixed (tied for 17th in runs saved and tied for 7th (with Houston) for fewest errors committed), but it generally helps the Mariners more than hurts them.

Most Dangerous Player: C Cal Raleigh. Sure, there are plenty of Astros-killers on the roster (see Julio Rodriguez and Randy Azorarena), but let’s not over-complicate this. Big Dumper is lumbering towards 60 dongers. While he hasn’t lit up Houston like other teams, this series is a forum for him to overtake Judge and cement the #1 candidate for AL MVP slot. Houston’s rotation can’t make any mistakes with him at bat, especially with everything at stake.

Injuries: The Seattle players on IL:

P Gregory Santos (knee); 60-Day IL; Projected Return: Late September
P Logan Evans (elbow); 15-Day IL; Projected Return: Late September
2B Ryan Bliss (knee); 60-Day IL; Projected Return: 2026
P Jackson Kowar (shoulder); 15-Day IL; Projected Return: TBD
P Trent Thornton (Achilles); 60-Day IL; Projected Return: 2026

Intangibles: Up until the calendar turned to September, things must have been incredibly frustrating for the Mariners. Their long-time tormentor in Houston was stumbling and bumbling through the post-All Star Break schedule, but Seattle could not overtake them. They got to a tie at one point in late August, only to see Houston up that lead back up to over 3 games. However, since September started, Seattle has feasted on a weaker schedule, especially at home. After the collapse of last season, it must feel great to be really back in the hunt. There is no dealing with an interim manager, so the focus is fully on the field. While some of the trade deadline acquisitions haven’t played at pre-trade levels, the Mariners bring a lot of late momentum to the party. Good time to be a Mariners fan…provided they can actually finish the story and get back to the postseason.

Series Outlook: Welcome to the biggest home series of the season for the Astros. While there will be six games after this, likely this series will ultimately decide the AL West. Maybe the Rangers will still have something to say on the matter, but their overall playoff hopes took a beating in the recent sweep in Houston. Save a few weeks in April, it has either been Houston or Seattle leading the West. May as well come down to these two. Seattle is far worse on the road, but they have cleaned up in divisional games. The loser of the series is by no means eliminated from the playoffs, but if either team is swept…well, Texas and Cleveland are still lurking as playoff understudies, ready to strike if Houston or Seattle collapses. Likely Houston will have its potential playoff starting rotation preview for this series (pending what happens the following week). It is entirely possible that this isn’t the last series between these two before the 2025 season and postseason bids adios. Keep that heart medication nearby…and call ahead to get the refill. Might be in short supply in Houston for the near-future.

NATIONAL COVERAGE: (Yeah, ESPN was going to grab this one for Sunday Night, but surprisingly, no national coverage for the other two games, especially since this is the only division in MLB where there is a tie for 1st this late in the season.)