If you asked this question a month ago, you would have been met with laughter. However, the Mariners stormed to a 21-6 record in August, and now have sole possession of first place in the American League West. The hottest team in baseball has the third-best record in the American League and has the right roster construction to make a deep playoff run.
Offense Heating Up at the Right Time
Seattle is only sixth in the AL in runs scored, but that number is heavily influenced by their poor hitting to start the season. The team had an OPS of just .672 in April but showed some progress by posting a .708 OPS and .701 OPS in May and June, respectively. In July, however, the team combined for an OPS of .763 as they hit a then-season-high 34 home runs.
In August, the offense was even better. That previous high-water mark for home runs has been smashed, with the Mariners hitting 46 last month. As a team, they slashed .285/.371/.493/.864 en route to the second-most runs in the AL. The level of production seen in August may not be sustainable, but scoring at a rate somewhere between what Seattle did in July and August would make them a formidable playoff opponent.
The Pitching Staff
The Mariners pitchers have done the best job of keeping runs off the scoreboard of any staff in the MLB. They rank first in the league in ERA and are tied for first in overall runs allowed. Ace Luis Castillo is a legitimate Cy Young contender, and it could be argued that youngster George Kirby has been just as good, if not better. Logan Gilbert has been rock-solid as well.
Those three pitchers, who all rank in the top 20 in the MLB in fWar, will anchor an elite starting rotation in the playoffs. Additionally, Seattle has great depth. Presumptive fourth starter Bryce Miller has had a great rookie season, and fellow rookie Bryan Woo has had good moments as well.
The Mariners' bullpen has been every bit as good as their starters, as according to MLB.com, the relievers have the second-best ERA of any bullpen in the MLB. The combination of a deadly starting rotation coupled with a bullpen that can effectively close out games has allowed Seattle to have the best pitching in the MLB in 2023.
How Deep of a Playoff Run Can the Mariners Make?
The answer to this question is going to depend on the bats. Seattle will be able to limit the scoring of their opponents and keep games close. If the offensive production equals that of the early-season Mariners, the run will be quite short. However, if the runs get put up at the rate of the last two months, I don't think it's a stretch to say that this team could walk away from October with a World Series victory.