What's gone wrong for Mariners during September swoon?

SEATTLE -- The Mariners knew that their September slate wouldn’t be easy, even in the wake of their historic August ascent. Sunday’s 6-1 loss to the Dodgers served as the latest, and starkest, reminder that their path to the postseason would always require a sustained climb.

Seattle was swept for just the third time this season and the first since early June in Arlington. With it, the club tumbled further out of a postseason position with just two weeks remaining.

• Games remaining (13): at OAK (3), at TEX (3), vs. HOU (3), vs. TEX (4)
• Standings update: The Mariners (81-68) trail the Rangers (82-67) by a game for the third AL Wild Card spot. Seattle is 2 1/2 games behind the Astros (84-66) for the AL West lead.
• Tiebreakers: Win vs. Houston; losing vs. Texas (1-5); likely win vs. Toronto.

Making matters more troubling was that Los Angeles, which celebrated its NL West title into the late hours the night prior, rested most of its starters and deployed a bullpen game, making this matinee as seemingly winnable as any contest on this 2-4 homestand.

The loss was Seattle’s 11th in 16 games in September, over which it has a minus-16 run differential. Across the AL, only the White Sox and Angels have worse records this month.

Here is a look at what’s gone wrong:

Lacking the timely hit
The Mariners weren’t short of traffic this week, but they largely were unable to cash in.

After J.P. Crawford took ownership for the Nos. 1-3 hitters all striking out with runners on in the eighth inning on Saturday, the shortstop ripped an RBI single with the bases loaded in the second inning on Sunday. However, Julio Rodríguez grounded out to the pitcher before more damage could be done, and the Mariners went scoreless the rest of the way.

On Sunday, they went 2-for-10 with runners in scoring position to drop their September OPS in those situations to .599 (fourth lowest in MLB) after posting a .772 mark in August. Moreover, their 64 runs scored in September are fifth fewest in MLB.

“I don't think it's for lack of effort, and I don't think we're swinging at that many bad pitches,” manager Scott Servais said. “There will be one or two per at-bat that could hurt you. Sometimes you get outexecuted, you get beat.”

Pitching hiccups
Logan Gilbert has been the Mariners’ “stopper” throughout the second half, but he became the latest Seattle starter to stumble this month, pitching just five innings on Sunday while surrendering five runs on seven hits and a walk. His issue was hard contact, including two homers.

“We needed [to win],” Gilbert said. “This one was a really big game and we needed a better performance. So, it's frustrating. Not much I can do now, just try to clean it up. We've got very big games ahead of us. So it's tough to just say, but try to move on.”

The Mariners’ rotation rebounded some on this homestand, particularly thanks to scoreless starts from rookies Bryan Woo and Bryce Miller, along with the 17th quality start from Luis Castillo. But beyond Gilbert, George Kirby is still searching for answers after a month-long stretch in which he has a 6.00 ERA, as the Mariners have lost his past four starts. Either of those two would line up behind Castillo for any postseason Game 2.

The bullpen has bounced back after a tough road trip that ended Sept. 10. Yet overall, a pitching staff that has been among MLB’s best all year in September has a 4.57 ERA (18th in MLB) and entered Sunday worth 0.6 wins above replacement for the month, per FanGraphs -- ranked 23rd in the Majors.

Tougher opponents
There’s also the blunt reality that September baseball presents far more challenges. Contending teams are looking to push through to the postseason, while clubs out of it typically deploy younger players looking to make a strong impression for 2024. The Oakland club that awaits the Mariners on Monday falls into the latter category and just this week won a series in Houston.

The Mariners have also been tasked with a tougher schedule than their relatively light August, when they played only six of their 27 games against teams above .500. Only two of their series came against teams currently holding or within a game of a playoff spot. But in September through the end of the season, 20 of Seattle’s 29 games have been or will be against teams above .500. Six of those series are against teams currently holding or within a game of a playoff spot.

This final stretch ends with a 10-game gauntlet beginning Friday, when the Mariners exclusively face Texas and Houston to finish the year. Essentially, Seattle’s playoffs will begin a week and a half early.