Mariners vs Astros: How This Series Could Decide the AL West
In 2001, the Seattle Mariners had a team of misfits that many sportsbooks expected to finish below .500 and an ESPN simulation projecting them for third place in a four-team division. Despite the modest preseason outlook, Seattle buzzed with excitement as future Hall of Famer Ichiro began his first MLB season after a legendary career in Japan. With a team of proven veterans such as Edgar Martinez, Dan Wilson, Jamie Moyer, and John Olerud, alongside rising stars like Brett Boone, Mike Cameron, and Freddy Garcia, the Mariners shattered expectations by winning an MLB-record 116 games. Sadly, that remains the last time Seattle captured the AL West crown.
Today, the Seattle Mariners are at a crossroads. Their upcoming series against the Houston Astros, starting Friday, is more than just another set of games. It is a potential turning point in the AL West race. Every win or loss could reshape the division standings, impact playoff positioning, and alter the team’s chances of making a deep run in October. Using the Mariners Playoff Odds Simulator, we can break down exactly what is on the line for Seattle in each scenario.
Right now, the Mariners are in great position not only to secure a playoff berth but also to make a serious push for the AL West crown. Winning the division would most likely slot them into the number three seed in the American League, giving them the invaluable advantage of hosting the Wild Card Round at T-Mobile Park.
And while the division should be the primary target, there is an outside shot at something even bigger. If the Mariners stay hot and catch fire down the stretch, they could leapfrog the Detroit Tigers for the number two seed. The Tigers currently hold a three game edge, but Seattle owns the all important tiebreaker. That matters because a number one or number two seed comes with the ultimate reward: a bye straight into the ALDS.
That might be dreaming a bit too far ahead though. The real prize is right in front of them, the AL West. A series win, or better yet a sweep against Houston, could finally deliver something Mariners fans have not seen since 2001, a division title.
What If Scenarios - Mariners vs Astros Series
The Mariners have a big series against the Kansas City Royals coming up, and that one definitely matters. But I wanted to highlight the significance of the Astros series, because to me they are our true arch nemesis. If the Mariners get swept by Houston, the season is far from over, but the playoff picture darkens quickly. On the other hand, if Seattle sweeps the Astros, they could be in line not only for the AL West crown but possibly even the number two seed in the American League and a Wild Card Round bye. Nothing is guaranteed, but the simulator gives us a fun and lighthearted way to ask: What are the Mariners’ odds of making the playoffs, winning the division, or even winning the World Series?
Unlike the Fangraphs playoff odds, the Grand Salami Time Playoff Simulation lets you control the outcomes. You can pick whether the Mariners win or lose any future game and instantly see how the odds shift. It is dynamic, updates every 15 minutes, and you do not have to wait until tomorrow to know where things stand.
Scenario 1: Mariners Get Swept by Astros (0-3)
If the Mariners get swept by Houston, the consequences are immediate and painful. Seattle would lose any tiebreaker opportunity in the AL West and risk damaging their overall playoff positioning. Even in that outcome the Mariners’ playoff odds remain solid, but their path to a division title becomes extremely narrow.
Playoff Odds: Seattle would still sit at 78.7%. On paper that looks strong, but for a team that has missed the postseason by just one game in each of the past two years, it leaves very little margin for error.
AL West Odds: A sweep drops their chance of winning the division to just 6.9%.
World Series Odds: Seattle’s title hopes would slip to 3.1%. More troubling, they would likely slide into the number six seed and be forced to open the Wild Card Round on the road… against none other than the likely #3 seeded AL West champion Astros.
A sweep would be a tough blow. Momentum is key in October, and this scenario puts Seattle in a likely Wild Card Spot
Potential Outcome: Mariners get 3rd wild card spot (AL 6th Seed) and play Astros (AL 3rd Seed) in the Wild Card Round. Astros would have the home field advantage.
Scenario 2: Mariners Lose Series 1-2
A 1-2 loss softens the damage, but it still leaves Seattle a huge disadvantage in winning the Division, especially since losing this series means we do not have the tie-breaker against the Astros. The Mariners need to go 2-1 to win the tiebreaker which is a huge deal in terms of winning the AL West.
Playoff Odds: Seattle would have a roughly 90% chance to make the playoffs if the Mariners take just one of two games against the Astros. 90% chance is not quite a sure thing, but I would put money on Steph Curry hitting any given free-throw.
AL West Odds: Going 1-2 still gives the Seattle Mariners a 31% chance to win the AL West. Without the tie-breaker, the Ms would really have to win the majority of our other remaining series to win the AL West and not win this series.
World Series Odds: Seattle’s title hopes would jump slightly to 4.6%. Part of this jump is because the Mariners are more likely to be in the playoffs, but a portion of this increase is due to potential better seeding in the playoffs (compared to if the Ms got swept by the Houston Astros).
Potential Outcome: Mariners still get 3rd wild card spot (AL 6th Seed) and play Astros (AL 3rd Seed) in the Wild Card Round. Houston Astros would have the Home Field Advantage during the series.
Other potential opponents are the Boston Red Sox or the New York Yankees if the Mariners end up with a better wild card spot.
Scenario 3: Mariners Win Series 2-1
Winning two out of three against Houston provides the biggest boost toward claiming the AL West. That single extra win carries double weight because it gives the Mariners the head-to-head tiebreaker over the Astros. In effect, it is like picking up two games in the standings.
If the series reaches a rubber match with the teams tied at 1–1, the finale could become the most meaningful game of the Mariners’ season. The stakes would not just be about another win in the standings, but about securing a crucial advantage that could decide the division title.
Playoff Odds: Seattle would have a roughly 98% chance to make the playoffs if the Ms take two.
AL West Odds: this is by far the largest swing at our AL West Odds. The Division Title Odds jumped from 31% to 83% due to this one extra win. Take a look for yourself at the charts below, where you will find all the Green Bars, meaning The Mariners Win the Division.
World Series Odds: Seattle’s World Series hopes increase 6.7%. Part of this jump is because the Mariners are more likely to be in the playoffs, but a portion of this increase is due to potential better seeding in the playoffs.
Potential Outcome: Mariners will win the AL West (AL 3rd Seed) and play against the Astros (6th seed). Mariners would have home field advantage.
Scenario 4: Mariners Sweep Houston (3-0)
A sweep would be seismic for the Mariners and the AL West.
Playoff Odds: Making the playoffs is all but guaranteed if the Mariners sweep the Astros. Out of the entire 1000 simulations, the Mariners only did not make the playoffs 1 time when we swept the Astros. This gives the Mariners a 99.9% chance to make the playoffs with a sweep.
AL West Odds: It is not a sure thing, but 97% is almost as close as it can get.
World Series Odds: The Mariners would have a solid jump to 8.6% in playoff odds. Keep in mind this is conservative based on the team record methodology.
Potential Outcome: Mariners will win the AL West (AL 3rd Seed) and play against the Astros (6th seed). Mariners would have home field advantage.
Another more unlikely but very possible outcome if the Ms sweep the Astros is that the Mariners end up with the 2nd seed in the AL, and get a bye for the Wild Card round.
Takeaways
Winning the AL West likely does not give us a bye during the first round of the playoffs, but it means a lot to the town and organization. Winning 2 out of 3 against the Astros and winning the AL West is worth a banner and Mariners should take it.
These odds are using the record based and strength of schedule methodology in our playoff Odds Simulation. We also have a Roster Adjusted WAR based Model that you can switch to that is closer to what Fan-Graphs would have. It takes into account the trade deadline pickups of Eugenio Suarez and Josh Naylor. Feel free to play around with the Playoff Odds Simulator for yourself!
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