MLB Baseball: Arizona Diamondbacks vs. Seattle Mariners Preview, Prediction & Odds - Sept. 12, 2021

by Chuck Sommers

Game time: 4:10 p.m. ET
Venue: T-Mobile Park, Seattle, WA
Where to watch: Bally Sports Arizona, ROOTNW

Opening Odds at USA Sportsbooks

DraftKings: Mariners -190, D-Backs +160
Caesars: Mariners -180, D-Backs +165

Season record (entering Saturday)
Diamondbacks: 45-96 (Last place, NL West)
Mariners: 77-64 (T-2nd place, AL West)

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Diamondbacks - Mariners preview and analysis

Recent form
Diamondbacks: Lost 6 straight
Mariners: 7-3 in last 10

Perhaps destiny wants the Seattle Mariners to make the playoffs after all.

For as long as the teams around them falter to the ground, the Mariners have all the reason in the world to feel confident that they will be playing in October.

But they’ll need to take care of business in front of them, and that includes ending a three-game series against the Arizona Diamondbacks on Sunday in Seattle.

The Mariners took Game 1 5-4 on Friday led by two home runs from Tom Murphy. The win put the Mariners within one game of the New York Yankees for the second wild-card spot in the American League and only two games from the top spot occupied by the Boston Red Sox.

There is still hope for the Mariners to catch the Houston Astros, trailing by 5.5 games, but they’ll at least be in second place thanks to the Oakland Athletics losing Saturday to the Texas Rangers in their come-from-behind efforts.

Seattle, pending the Toronto Blue Jays’ effort against the Baltimore Orioles on Saturday, could find themselves all alone in the wild card picture. Should whatever happen with the Yankees against the New York Mets come to fruition, this game against the Diamondbacks could hold more merit than we initially thought.

Seattle enters Saturday winners of seven of nine thanks to Marco Gonzales throwing six scoreless innings and striking out three. Although he had to throw 101 pitches, Gonzales did more than enough to silence the Arizona offense. Seattle did more than enough to get to Madison Bumgarner (6 IP, 5 ER, 6 K, 1 BB).

The Diamondbacks lost for the sixth straight game and 11th time in 12 games. Henry Ramos hit a two-run home run in the losing effort for the team that’s likely to hit 100 losses first before anyone else.


There’s really nothing to this. The Diamondbacks are struggling, and the Mariners see playoff baseball in sight for the first time in a very long time. We should expect the Mariners to win this game and keep the momentum rolling. Mariners win 8-1.

Betting trends

The Diamondbacks are 17-50 this season when an underdog of +150 or more and are 1-14 against AL West teams this season.

Seattle is 10-9 when a favorite of -125 to -175.

Players to watch

Diamondbacks: Former first-round pick Seth Beer (No. 28 overall in 2018) hit his first major-league home run on Friday in a pinch-hit effort for Arizona.

Mariners: Contact is foreign, but the power isn’t for Kyle Seager. The former All-Star is batting .198 in his last 23 games, but has hit nine homers to 22 RBI.

Projected lineups:

Nick Ahmed (R) SS
Ketel Marte (S) CF
Carson Kelly (R) C
Christian Walker (R) DH
Pavin Smith (L) 1B
Andrew Young (R) 2B
Josh Rojas (L) 3B
Henry Ramos (S) LF
Jake McCarthy (L) RF

J.P. Crawford (L) SS
Mitch Haniger (R) RF
Kyle Seager (L) 3B
Ty France (R) 1B
Abraham Toro (S) 2B
Luis Torrens (R) DH
Jarred Kelenic (L) CF
Tom Murphy (R) C
Jose Marmolejos (L) LF

Probable starting pitchers: Tyler Gilbert (ARI) vs. Yusei Kikuchi (SEA)

Statistical leaders:

Batting average: Josh Rojas (.270)
Hits: Pavin Smith (122)
Home runs: Josh Rojas (11)
RBI: David Peralta (55)
Stolen bases: Josh Rojas (7)
Wins: Merrill Kelly (7)
Saves: Tyler Clippard (5)
ERA: Merrill Kelly (4.30)

Batting average: Ty France (.291)
Hits: Ty France (144)
Home runs: Kyle Seager (34)
RBI: Kyle Seager (94)
Stolen bases: Dylan Moore (20)
Wins: Chris Flexen (11)
Saves: Kendall Graveman (10)
ERA: Chris Flexen (3.56)

Don't miss our champion handicappers' free picks and expert MLB picks today. And if you enjoyed this Arizona Diamondbacks - Seattle Mariners prediction, be sure to drop by every day for our daily MLB projections and previews.

Chuck Sommers

About the Author:

Chuck Sommers has camped outside of sportsbooks since he can remember, learning the tricks and nuances of the trade. He still has nightmares of betting $5,000 on the Raiders in the Tuck Rule game but has since turned that to 25 years of veteran handicapping greatness. You can find him mostly in the shadows at the Red Rock or Aliante casinos wondering if the over is cashing on any given Sunday.

All photographic images used for editorial content have been licensed from the Associated Press.

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