Remaining in the AL Wild Card chase until the final day of the season energized the Seattle Mariners fan base in a way rarely seen in the last two decades. So much so, fans are believing that 2022 will be the year the Mariners finally become a legitimate threat to win the AL West division championship.

That is an exciting proposition. But there is an unavoidable truth that could potentially scuttle such lofty expectations. Even at its best, the Mariners’ starting rotation did not approach the excellence delivered by the starting staffs of baseball’s best teams – not even close.

Yes, that sounds harsh. But it is true.

Efficient And Effective

Before addressing my assertion any further, we should first establish when the Mariners’ starting staff was actually at its best. That is not hard to do. The rotation reached peak performance following the arrival of Tyler Anderson on July 30. From that point moving forward, Seattle’s starting pitching was both efficient and effective.

M's Rotation Pre/Post Tyler Anderson's Arrival

Anderson’s presence provided something the rotation sorely lacked before his arrival – stability. Injuries and ineffectiveness forced manager Scott Servais to use 14 starters prior to the 31-year-old joining the team. Afterwards, Servais only needed five starters for the final two months of the season.

Although the overall improvement of the rotation isn’t solely attributable to Anderson, his veteran presence and consistency on the mound played a pivotal role in the staff’s renaissance. Particularly with Yusei Kikuchi struggling in the second half of the season.

Kikuchi was the team’s lone All-Star game representative – a richly deserved honor. Unfortunately, his season went sideways following his first July start. For the remainder of the year, the 30-year-old labored to deliver competitive outings just when the Mariners needed him most. Servais subsequently sidelined the southpaw for the final week of the season.

Rounding out the starting five along with Anderson and Kikuchi were Marco Gonzales, Chris Flexen, and rookie Logan Gilbert. All three delivered their best efforts down the home stretch.

After struggling during the first half of the season and missing the month of May due to a flexor strain, Gonzales regained his form during the final two months of the season posting a .274 xwOBA, which was top-15 among his peers. When the Mariners needed him most, the Gonzaga alum demonstrated the mettle of a champion.

Expected Weighted On-Base Average (xwOBA) uses quality of contact (exit velocity and launch angle) to determine what should’ve happened to batted balls. A key advantage to xwOBA is defense (good or bad) doesn’t influence it. This gives us a truer sense of how a hitter or pitcher is performing. MLB league-average xwOBA = .314

Little did we know in Spring Training that signing Flexen out of the KBO would be a coup for President of Baseball Operations Jerry Dipoto and his staff. The 27-year-old was the team’s most consistent arm and the only Seattle pitcher from the Opening Day roster to make every scheduled start. All told, Flexen pitched 179.2 innings – seventh most logged by an AL starter in 2021. An impressive accomplishment considering the Mariners used a six-man rotation until late-June.

When Gilbert debuted in May, he was the organization’s top pitching prospect. It was not always smooth sailing for the 24-year-old, although he demonstrated growth as the season progressed. By September, the Stetson product was arguably the best starter on the staff.

Logan Gilbert’s September Stats And Team Ranking
2.70 ERA (1st)
3.59 FIP (1st)
23.0 SO% (1st)
5.9 BB% (1st)
1.02 WHIP (2nd)
.205 AVG (2nd)
0.7 fWAR (1st)

During the last two months of the season, Gonzales, Flexen, Anderson, and Gilbert formed a reliable starting four. As a result, the Mariners were able to compete for the postseason until game-162.

So, why my concern?

Nice, But Not Great

The upgraded version of the Mariners’ rotation was a nice story – for a fringe contender. Not so much for a team trying to be great with its focus on winning the World Series

The following helps illustrate the statistical gap between Seattle’s rotation at its peak and the starting staffs of the clubs with the three best records in the AL and NL – the Giants, Dodgers, Rays, Astros, Brewers, and White Sox. This is the level of excellence the Mariners should be striving to attain.

Revamped M's Rotation vs Baseball's Six Best Teams
* Averages for starting pitchers

Other than walk rate, the revamped Mariners rotation trailed our “Big Six” by a significant amount. Realistically, Seattle starters were collectively average-ish when the going was good.

Value Added?

When the FanGraphs version of wins above replacement (fWAR) is used to gauge Servais’ starters, we receive the same message that the preceding table delivered. The rotation’s difference-makers were good, but not elite. The highest ranked Mariner with 110-plus innings was Flexen (3.0 fWAR) at number-39.

Starter fWAR and MLB Rankings
Chris Flexen – 3.0 fWAR (39)
Logan Gilbert – 2.2 fWAR (53)
Tyler Anderson – 2.2 fWAR (56)*
Yusei Kikuchi – 1.1 fWAR (82)
Marco Gonzales – 0.6 fWAR (95)

* Includes Anderson’s time with Pittsburgh

Once again, we are confronted with the reality that the Mariners will need better production from its 2022 rotation to become serious contenders for the AL West division title.

Remember, the World Series is the endgame – not flirtation with a wild card berth.

But The Kids…

Some fans will suggest help is on the way from Seattle’s stacked farm system. The organization does have a bevy of young arms seemingly ready to make the jump from Double-A to the majors. The most recognizable names being Matt BrashEmerson HancockGeorge KirbyLevi Stoudt, and Brandon Williamson.

Still, that is a lot of youth and uncertainty to bank on heading into a regular season. Particularly for a club wanting to compete at the highest level. To be clear, I am not suggesting these young guns will not contribute in 2022. But expecting great things upon arrival is fraught with risk. Remember, Gilbert endured struggles before finding his groove in September.

Looking Ahead

How the Mariners choose to construct the 2022 rotation will certainly be central to Hot Stove speculation.

Will the front office stick with the 2021 gang and wait for the kids to arrive?

Will adding more veteran depth be the plan instead?

Could acquiring a top-shelf arm be the priority?

Regardless of the strategy management employs, the Mariners should begin next season with a more robust and dependable starting staff than the 2021 Opening Day version. This is a good thing. How good depends on what Dipoto and crew do to improve the starting rotation during the offseason.

I suspect it will be a busy winter at the corner of Edgar & Dave.

My Oh My…

Got a take on what you just read? Talk about it here!

Image courtesy of Elaine Thompson /AP Images
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Luke Arkins

Luke is a native New Yorker, who grew up as a Mets fan. After the US Navy moved him to the Pacific Northwest in 2009, he decided to make Seattle his home. In 2014, Luke joined the Prospect Insider team. During baseball season, he can often be found observing the local team at T-Mobile Park. You can follow Luke on Twitter @luke_arkins


  1. It’s not hard at all. Seattle is probably not signing a long-term free agent starter since most of them are 30+, but other than that, it’s easy. You don’t plan to win by not adding help because you don’t want to block prospects.

  2. I agree totally with your assessment of our starting pitchers and getting a top of the starting rotation pitcher probably not come From free agency the more likely trade I like Kyle Hendricks of the Cubs in a trade the five minor league pitchers You named would be great for an expansion team first staff were three or four of them breaking out for a solid second year

  3. It’s hard to want to bring in an expensive arm with so much talent in the wings, especially when those expensive arms aren’t a sure thing. I’d rather try to bring back the four then replace Kikuchi with Paxton and start giving the kids some spot starts as injury replacements. Trade Dunn and Sheffield. If we could find a higher tier starter that would take a two-year contract great but that would be a tough get.

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