The ragtag, scrappy Houston Astros host the big, bad Seattle Mariners this weekend, including the series finale on “Sunday Night Baseball” at 7 p.m. ET on ESPN, in a series that might decide the American League West — as the pair is tied atop the division.

Wait … what?

That’s right. The Astros, who have won seven consecutive full-season AL West division titles, are rightfully described as the underdog. How are they even in this position? They traded Kyle Tucker, lost Alex Bregman in free agency, have played most of the season without Yordan Alvarez, lost Jeremy Pena for over a month, have just two pitchers with at least 15 starts and have been without Josh Hader since early August. In ESPN’s preseason predictions, only three of 28 voters picked them to win the division.

The Mariners, meanwhile, are fighting to win their first division title since 2001. Only the Miami Marlins and Colorado Rockies, who have never finished in first place, and the Pittsburgh Pirates, who last won in 1992, have gone longer without a division title. Yet, when the Mariners acquired Eugenio Suarez and Josh Naylor at the trade deadline, many pundits believed they were now the team to beat in the AL.

What will decide the AL West title over these final 10 days of the season?

The Astros and Mariners are tied in the season series at 5-5, so whoever wins the weekend series will own the all-important tiebreaker. The Texas Rangers, after the Astros just swept them, are all but eliminated from the division race, so it’s just between Seattle and Houston now.

Here are five key questions to the division:

1. What will Cal Raleigh do for a final encore?

After hitting under .200 in both July and August (while still mashing 17 home runs), Raleigh has been mixing in a few more singles with his home runs in September and has an OPS over 1.000 for the month heading into the start of the series. He has still missed just three games all season and, with the Mariners fighting for their playoff life down the stretch, hasn’t missed a game since July 23. Even with DH games mixed in, that’s a phenomenal workload (only J.T. Realmuto and William Contreras have caught more innings this season). It seemed as if Raleigh hit the wall a bit in August, but playoff fever erases all fatigue.

Indeed, Raleigh keeps hitting home runs and he has great numbers with runners on base — an OPS over 1.000 with runners in scoring position and over 1.100 in high-leverage situations, both higher than his overall season OPS. The Astros, however, are one team that has contained Raleigh in 2025. In 10 games against Houston entering this series, Raleigh has hit just .190/.244/.286 with one home run and three RBIs.

2. Can the Astros score runs without Alvarez?

Alvarez missed 100 games with a broken bone in his hand before finally returning on Aug. 26. He hit .369/.462/.569 in 19 games before suffering a severe ankle sprain while scoring a run in Monday’s win over the Rangers. The Astros rallied to win that game without him and the next two as well, but even after the trade deadline acquisitions of Carlos Correa and Jesus Sanchez, they’ve struggled at times to score runs. This is the worst offense for the Astros since the rebuilding year of 2014 — in the full seasons from 2017 to 2023, they averaged 231 home runs per season before dropping to 190 last year and just 169 so far in 2025.

The Astros haven’t put a timetable on Alvarez’s return, but manager Joe Espada said Wednesday that injured third baseman Isaac Paredes, who has been out since July 19 with a hamstring strain, might be back “sooner rather than later.” But with Correa locked into third base, where will Paredes play? He could play first base, although Christian Walker has been better in the second half. He could DH, although that means playing Jose Altuve in the field every day. If Alvarez makes it back, it seems likely it will be only as a DH and not in left field, where he started nine times since coming off the injured list. Maybe Paredes will play some second base, where he did play 57 games in 2022-23. In the end, if Houston can somehow get both Alvarez and Paredes back, too many players will be a good problem to have.

3. Which bullpen will finish strong?

At the end of July, the Astros ranked fifth in the majors with a 3.39 bullpen ERA, getting outstanding work not just from Hader but less heralded names such as Bennett Sousa (2.66 ERA at the time), Bryan King (2.78 ERA) and Steven Okert (2.98 ERA) — like Hader, all lefties. That left Bryan Abreu as the lone high-leverage righty in the pen, so it was a clear concern whether the lefty-heavy pen could hold up.

With Hader perfect in his save chances, the Astros still rank first in the majors in bullpen win probability added, but he last pitched Aug. 8 — and since the beginning of August, Houston’s bullpen has a 4.53 ERA. Abreu is 7-for-8 in save opportunities filling in for Hader but has allowed eight runs in his past seven innings entering the Seattle series. King has remained effective, Sousa and Okert less so, with Sousa on the IL and GM Dana Brown saying he could return at some point during the postseason in a “best-case scenario.” The Astros even signed Craig Kimbrel off the scrap heap in mid-August and have given him some high-leverage innings.

The Mariners rank fourth in bullpen WPA, so it has been a strength throughout the season, but both closer Andres Munoz and top setup man Matt Brash have been a little shaky of late. The Mariners saw their 10-game winning streak snapped Wednesday when Brash blew a 4-3 lead in the eighth inning by giving up a two-run home run to light-hitting Adam Frazier. That was Brash’s second straight game allowing a home run and he has a 5.19 ERA over his past 19 appearances. Munoz has a 1.54 ERA but has still managed seven blown saves (two of those were ghost runners in extra innings). He has walked the tightrope a lot of late. There will be no margin for error in these final games.

4. Which team will clean up in the final week?

Unless there’s a sweep this weekend that creates some space between the two teams, the final week of games will then decide the race. The Mariners finish at home with six games against the Rockies and Los Angeles Dodgers, while the Astros go on the road to play the Athletics and Los Angeles Angels. Keep in mind that with the Detroit Tigers slumping of late, the No. 2 seed in the AL behind the Toronto Blue Jays remains in play as well. Detroit owns the tiebreaker over Houston, but Seattle holds the tiebreaker over Detroit.

Factor in that a surging Cleveland Guardians team still has a shot at that third wild card (whether it’s over Boston or the Seattle-Houston loser), and the Mariners or Astros could end up anywhere from the second seed in the postseason to completely out of it.

Seattle has played much better at home — 48-27 — so you have to like its chances of sweeping the lowly Rockies, although the Mariners’ three best starters (Bryan Woo, George Kirby, Logan Gilbert) will start against Houston. The Dodgers are too far behind the Milwaukee Brewers and Philadelphia Phillies for one of the top two seeds, so they’re already locked in to a wild-card series. Even though the Dodgers might still be battling the San Diego Padres for the NL West title that final weekend, they will be concerned about getting their top starters lined up for the first-round series, so the Mariners might miss Yoshinobu Yamamoto, Blake Snell and Shohei Ohtani. Advantage Seattle?

On the other hand, the Astros get two teams playing out the string. The Angels, in particular, look like a potential sweep, even though the series is in Anaheim. Advantage Houston? Well, the A’s have been over .500 since the All-Star break, so that won’t be an easy series.

Bottom line: Both teams might go 5-1 that final week. Whoever enters the week with the lead will have the edge.

5. Can the Mariners overcome their own history?

On paper, the Mariners appear to be the better team, with more frontline talent and the better run differential. Though they’ve gone through ups and downs all season — usually dependent on whether they’re at home or on the road — the recent 10-game winning streak suggests they might be hot at the right time. Friday’s game seems like one of the most crucial of the entire season, in a must-see battle of aces: Seattle’s Bryan Woo vs. Houston’s Hunter Brown.

Even though these aren’t the same Astros we’re used to seeing since 2017, this is a franchise that knows how to win, and this team has proved resilient beyond expectations, given all the injuries and the patched-together rotation beyond Brown and Framber Valdez. The sweep over the Rangers showed how this is still a team that can step up in the big games.

The Mariners, meanwhile, come down to the final week with a playoff spot up in the air, and their history is not good in this regard:

2024: Fell one win short of the Tigers and Royals for a wild card.

2023: Fell one win short of the Blue Jays for a wild card (and two wins short of the AL West title).

2022: Made the playoffs for the first time since 2001.

2021: Eliminated on the final day of the regular season.

2016: One game out of a wild card with two left to play.

2014: Fell one win short of a wild card.

Baseball … it can be painful. However, when the Mariners made the playoffs in 2022, the clinching blow came from a young catcher named Cal Raleigh, who pinch-hit in the bottom of the ninth inning of a tie game and hit a walk-off home run that sent the Mariners to the postseason for the first time since 2001.

It has been the season of Cal, one home run after another. It’s asking a lot, but he might need one more week of heroics.