Whether it’s conventional stats or advanced metrics, numbers matter in baseball. For this reason, I cherry-picked a few Seattle Mariners stats to discuss.

The numbers you’ll see won’t paint a complete picture, but they may help shape expectations for the Hot Stove season and the 2021 Mariners. At the very least, these stats should foster a conversation about baseball, which is always fun.


Regular season games played by all but two teams. Considering there’s an ongoing pandemic, that’s an impressive feat. I was highly skeptical about MLB pulling it off. But they did and I happily admit being wrong.

Something to consider when discussing 2020. The season was a small sample size and we should remember this moving forward. After all, a player’s or team’s stats from any 60-game span within a normal 162-game schedule may not be representative of the final product.


The combined winning percentage of the Astros, Angels, and Rangers. Perhaps the underwhelming performances of Seattle’s division rivals compelled Mariners GM Jerry Dipoto to say he believes his team could compete for the postseason in 2021.


The Mariners’ record this year. The team struggled early going 8-19 through August 20 and appeared destined to contend for the number-one overall pick in the 2021 draft. Yet, manager Scott Servais and his squad rebounded with a 19-14 record afterwards.

It’s worth noting Seattle’s 2020 record closely resembles where the team stood through its first 60 games last year (25-35). That group enjoyed a torrid 13-2 start before plummeting to the AL West cellar.


The number of AL teams the Mariners didn’t face in 2020. Why does this matter? We don’t know how Seattle would’ve fared against some of the best teams in the league – the Rays, Yankees, Twins, Indians, and White Sox.

Sure, the Mariners would’ve played these clubs just 6-7 times each. But competing in a larger field would’ve provided us with a better sense for where the rebuilding team stands. This is especially pertinent considering Seattle played in arguably the weakest division in MLB.


Mariner rookies used in 2020. That’s more than any team with the Marlins (21), Cardinals (19), and Astros (19) trailing close behind. Unlike Seattle, those clubs reached the postseason.

Aaron FletcherAnthony MisiewiczBraden Bishop
Brady LailDonovan WaltonEvan White
Jake FraleyJoe HudsonJoey Gerber
Jose MarmolejosJoseph OdomJustin Dunn
Justus SheffieldKyle LewisLjay Newsome
Sam HaggertySeth FrankoffTaylor Guilbeau
Tim LopesWalker LockettYohan Ramirez
Zac Grotz

Several of the names listed above, including Kyle Lewis, Justus Sheffield, and Justin Dunn, debuted before the 2020 season, but retained their rookie status heading into this year. The steady stream of rookies with more on the way in 2021 signals the youth movement is in overdrive.


While we’re talking youth, the average age of Mariner pitchers per Baseball Reference was 26.6-years-old tying the team with Detroit for youngest in the majors. The Nationals were oldest at 30.8 years. Seattle’s most youthful pitchers were in their age-23 seasons – rookies Ljay Newsome and Joey Gerber. The staff’s graybeard was 36-year-old Yoshihisa Hirano.

Mariner hitters also averaged 26.6 years, which was third lowest behind Toronto (25.9) and Baltimore (26.3). The youngest position players were in their age-24 season – Luis Torrens, Shed Long, Evan White, and likely AL Rookie of the Year Kyle Lewis. At 32, Dee Strange-Gordon and Kyle Seager were the team’s senior citizens.


The Mariners’ ranking for total Defensive Runs Saved (DRS) in 2020. An impressive jump for a club that was number-29 a year ago.

DRS captures a player’s overall defensive performance by accounting for various aspects of their game – errors, range, outfielder arm and home run stealing ability, middle-infielder double plays, plus catcher stolen base prevention, pitch framing, and blocking.

Seattle’s best defenders were first baseman Evan White and shortstop J.P. Crawford – both tallied seven DRS this season. White led all qualified MLB first basemen, while Crawford finished in a tie with Houston’s Carlos Correa for second place behind Dansby Swanson (9) of Atlanta.

Overall, things are looking up from a defensive standpoint. That said; 2021 will be a transition year for the club as it introduces new players and determines the best position for several versatile holdovers. Expect early growing pains, which is okay for a club looking to the future.


The expected weighted on-base average (xwOBA) of Seattle’s starting rotation, which was thirteenth best in MLB. We know xwOBA relies on quality of contact (launch angle and exit velocity) and strikeouts and walks. Good pitchers have a positive influence over these elements.

In the Mariners’ case, three starters who faced 150-plus batters had an xwOBA better than the league-average for starters (.314) – Yusei Kikuchi (.279), Marco Gonzales (.291), and Justus Sheffield (.303). Furthermore, Nick Margevicius (.301) fell short of our 150-hitter criteria by one plate appearance.

Obviously, there’s room for improvement. Kikuchi managed to lead in xwOBA, yet his 5.17 ERA was worst on the starting staff. This is particularly troubling considering the relatively solid defense behind him. Moreover, Dunn posted a more respectable 4.34 ERA, but his .356 xwOBA ranked in the bottom 10-percent among MLB starters.

Despite these issues, the Mariners have established a foundation to build upon this offseason and in the future.


Since baseball integrated in 1947, only 10 pitchers qualifying for the ERA title have recorded a lower walk rate than Gonzales’ 2.5-percent this year. The lowest was Carlos Silva at 1.2-percent with the 2005 Twins.

It’s worth noting Kyle Hendricks of the Cubs had the same walk rate as Marco. Neither pitcher throws hard, yet both manage to succeed in an era when throwing over 95-MPH is commonplace.


Innings pitched by Seattle’s left-handed starting pitchers – tops in the majors with Oakland (123.2) a distant second. The main southpaw starters were Gonzales, Kikuchi, Sheffield, and Margevicius with Nestor Cortes Jr. making a 0.1 inning special guest appearance.


The number of pitchers in the Mariners’ 2020 rotation and most likely next year’s too. Although a 6-man rotation mitigates workload, it comes at a competitive cost. Over a full 162-game schedule, the best pitchers on a 6-man staff will start 5-6 fewer games than a 5-man crew.

Can the Mariners contend with less of Gonzales and Sheffield in 2021?


The rotation was a good news story, but the bullpen was not. Seattle relievers collectively had a .332 xwOBA. Only three teams were worse – the Phillies (.347), Marlins (.349), and Rockies (.355).

Although the bullpen ranked poorly, several relievers managers to stand out. Rookie Anthony Misiewicz made his mark with a .278 xwOBA and should figure prominently with the Mariners next year.

Rule 5 draft pick Yohan Ramírez recorded a .305 xwOBA despite inconsistent command and control. Opponents hit .130 against Ramírez – fourth lowest in the majors. However, his MLB-worst 21.3-percent walk rate produced a .351 OBP that ranked 264 of 323 big-league pitchers.

The bullpen did improve with a .316 xwOBA in September. Waiver-claim Casey Sadler (.247) performed well as did freshman Joey Gerber (.318) and Kendall Graveman (.310).

Graveman began the season in the rotation until a benign bone tumor in his neck prompted a bullpen role. How he fits into Seattle’s future plans is unclear. There’s a $3.5 million club option for 2021, but that may be too pricey considering the 29-year-old’s recent injury history and unproven record as a reliever.

Regardless of the outcome of Graveman’s situation, the bullpen needs an influx of dynamic arms. Especially if Dipoto is serious about contending for a postseason berth.


The Mariners’ On-base Plus Slugging Plus (OPS+) this year.

OPS+ normalizes On-base Plus Slugging percentage by accounting for factors such as league, ballpark, and era. League-average is always 100. Therefore, a player or team with a 120 OPS+ is 20-percent above average.

In Seattle’s case, a 91 OPS+ tells us the offense was nine-percent below average. It also ranked twentieth in the majors.

Historically, the Mariners have posted a lower OPS+ just nine times in 44 seasons. If you prefer conventional numbers, the team’s .226 batting average was its lowest ever. Furthermore, their OBP and SLG were among the 10 lowest in franchise history.

The current Mariners had just three players with 150-plus plate appearances with the team and an OPS+ over 100 – Dylan Moore (139), Lewis (126), and Seager (122). Only seven teams had fewer than three.

Note: Ty France had a combined 133 OPS+ with the Mariners and Padres. The player France was traded for – Austin Nola – had a 152 OPS with Seattle.

60 (Again)

Only four clubs hit fewer home runs than the Mariners’ 60 dingers this year. It’s worth noting the top eight clubs in home runs reached the postseason.

To be clear, it’s possible to play October baseball without hitting a ton of home runs. Cleveland and St. Louis ranked behind the Mariners, yet those clubs reached the playoffs. Still, teams hitting the most home runs in postseason games this year have emerged victorious nearly every time.


Stolen bases by the Mariners this year. Only the Padres (55) and Marlins (51) swiped more bags. Seattle’s stolen base tally actually exceeded the team’s totals during 112 games in 1994 and a full 162-game slate in 2013. Moore led the team with 12 swiped bags tying him for fourth most in the majors.


Yeah, this one is irrelevant, although it seemed fun. The average home run trot time for Sam Haggerty was 18.6 seconds.

Yes, Haggerty had just one dinger. But only Andrew Stevenson (17.3 seconds) of the Nationals and Brandon Nimmo (17.8 seconds) of the Mets were faster than the former New Mexico Lobo. At 28 seconds, Baltimore’s Pedro Severino had the slowest trot in MLB.


Current Mariners with guaranteed contracts for the 2021 season – Seager ($18.5 million), Kikuchi ($17 million), and Gonzales ($5.25 million). Two others have club options, but Seattle may choose to move on. Graveman and Strange-Gordon.

Why does this matter? The Mariners will have the financial flexibility to add talent, if management decides to do so this offseason. Publicly, Dipoto seems inclined to continue evaluating his cadre of youngsters and hold off on adding premium talent for now.


The MLB Pipeline ranking of George Kirby – the final prospect in the Mariners organization to appear on the outlet’s Top-100 list. Joining Kirby are Seattle prospects Jarred Kelenic (9), Julio Rodriguez (15), Emerson Hancock (30), Logan Gilbert (35), and Taylor Trammell (51).

Having so many top prospects is certainly a good thing for the Mariners. But becoming a sustainable winner will inevitably require help from outside the organization. Perhaps Dipoto inevitably trades some of these notable names to add reinforcements.


That brings us to our final entry. Yeah, you know what this signifies. It’s the number of years the Mariners have gone without a postseason appearance. This one needs to go away, right?

Yes, of course it does.

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