Arizona Diamondbacks vs Seattle Mariners Prediction, Preview and Odds - 05/29/2026

Game Time: 10:10 pm ET, Friday, May 29, 2026

Venue:  T-Mobile Park, Seattle, WA

Where to Watch:  MLB TV

DraftKings:  Moneyline odds:  Diamondbacks +123, Mariners -149; Over/Under:  7 runs

Bet365:  Moneyline odds:  Diamondbacks +125, Mariners -150; Over/Under:  7 runs

BetMGM:  Moneyline odds:  Diamondbacks +125, Mariners -150; Over/Under:  7 runs

Arizona Diamondbacks:  31-24 (2nd place, NL West)

Seattle Mariners:  28-29 (1st place, AL West)

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Arizona Diamondbacks:  9-1 last 10

Seattle Mariners:  6-4 last 10

The Diamondbacks are entering this series off a win and completed the sweep in their 3-game series against the San Francisco Giants 3-0 in their last series. They enter this game with a 31-24 record overall and have a road record of 13-14. This is the series opener of a 3-game series with the Mariners on Friday and they have Thursday off as a day of rest. Their offense ranks 10th in the MLB with a .716 OPS. Michael Soroka was their starting pitcher on Wednesday while Zac Gallen is making his start in this game on Friday. He is 3-4 with a 4.80 ERA this season. His team won their last 2 straight games this season with him making an appearance. In his last MLB regular season appearance, he allowed 3 ER, 0 HR, and 2 BB with 6 SO on 6 hits through 5.1 IP against the Colorado Rockies.

The Mariners are entering this series off a win and completed the sweep in their 3-game series against the Athletics 3-0 in their last series. They enter this game with a 28-29 record overall and have a home record of 14-15. This is the 1st game of a 3-game series with the Diamondbacks on Friday and they have Thursday off as a day of rest. Their offense ranks 16th in the MLB with a .700 OPS. Logan Gilbert was their starting pitcher on Wednesday while George Kirby is making his start in this game on Friday. He is 5-4 with a 3.54 ERA this season. His team lost their last 2 straight games this season with him making an appearance. In his last MLB regular season start, he allowed 3 earned runs, 0 homers, and 0 walks with 3 strikeouts on 9 hits through 6 innings pitched against the Kansas City Royals.

The current betting odds have the Diamondbacks listed as an underdog in this game according to Draftkings Sportsbook. The Diamondbacks have looked good in their games this season with their 31-24 record overall which has them right near the top of the NL West. They haven't been a great road team though with their 13-14 road record this year. Meanwhile, the Mariners haven't looked great in their games this season with their 28-29 record overall, but that record has them right at the top of the AL West. They haven't looked great in their own ballpark though with their 14-15 home record this season. The Mariners are 6-4 in their last 10 games now and they just took the lead in their division after sweeping the Athletics in their last series, but they still haven't looked great for a lot of the season and the Diamondbacks are starting to roll now. The Diamondbacks are 9-1 in their last 10 games and their offense has been getting better and better in these games. They are going with Gallen on the mound here and he hasn't looked great this season. He is 3-4 with a 4.80 ERA, but the team has been having success with him lately. They have won 2 games in a row now with him starting and he only gave up 3 earned runs in his last start too. The Mariners are going with Kirby in this one and he hasn't looked bad this season, but he hasn't looked great either. He is 5-4 with a 3.54 ERA and his team has had some trouble with him lately. They have lost 2 games in a row now with him starting and he gave up 3 earned runs in his last start which has been a common theme for him. Neither team has been pitching well lately, but the Diamondbacks have been a lot hotter entering this series and they do have the offensive edge which should be enough for them to squeak out a win in this series opener. The best way to place a bet here is on the Diamondbacks to win this game. 

Diamondbacks Mariners Prediction:  Our MLB Pick for Friday, May 29, 2026 (10:10 pm ET start time) is Diamondbacks 5 Mariners 4.

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Arizona Diamondbacks: 199-180 (+5.2 units) on the moneyline in all games. 94-94 (+9.6 units) on the moneyline in road games. 76-90 (+7.3 units) on the moneyline as an underdog of +100 or higher. 31-19 OVER as a road underdog of +125 to +175.

Seattle Mariners: 17-23 (-7.9 units) on the moneyline against NL West opponents. 209-184 (-10.6 units) on the moneyline in all games. 151-120 (-15.5 units) on the moneyline as a favorite of -110 or higher. 14-5 OVER after a win by 8 runs or more.

Arizona Diamondbacks:  L. Gurriel Jr. (LF) Ten Day IL - Hamstring. J. McCann (C) Ten Day IL - Quad. P. Smith (1B) Sixty Day IL - Elbow. C. Santana (1B) Ten Day IL - Groin. J. Lawlar (LF) Sixty Day IL - Wrist. C. Mena (SP) Sixty Day IL - Shoulder. B. Walston (SP) Sixty Day IL - Elbow. C. Burnes (SP) Sixty Day IL - Elbow. A. Puk (RP) Sixty Day IL - Elbow. J. Martinez (RP) Sixty Day IL - Elbow. A. Saalfrank (RP) Sixty Day IL - Shoulder.

Seattle Mariners:  B. Donovan (3B) Ten Day IL - Groin. C. Raleigh (C) Ten Day IL - Side. W. Wilson (3B) Ten Day IL - Thumb. M. Mastrobuoni (3B) Sixty Day IL - Calf. C. Vargas (RP) Sixty Day IL - Lat. L. Evans (SP) Sixty Day IL - Arm.

“There’s a high tolerance for pain and then he went out there and just started to squash the baseball. So it’s a fairly remarkable situation that he’s walked through and he’s having a fantastic year for so far." - Torey Lovullo on Corbin Carroll this season. 

“This is as good as we've played all season long, and as consistent as we've been. And again, it's all parts of the game.” - Dan Wilson after his team’s sweep of the Athletics in their last series. 

Ketel Marte (S) 2B

Corbin Carroll (L) RF

Geraldo Perdomo (S) SS

Adrian Del Castillo (L) DH

Ryan Waldschmidt (R) CF

Ildemaro Vargas (S) 1B

Jose Fernandez (R) 3B

Aramis Garcia (R) C

Tommy Troy (R) LF

J.P. Crawford (L) SS

Julio Rodríguez (R) CF

Randy Arozarena (R) DH

Josh Naylor (L) 1B

Rob Refsnyder (R) LF

Victor Robles (R) RF

Cole Young (L) 2B

Jhonny Pereda (R) C

Colt Emerson (L) 3B

Batting Average:  Tommy Troy (.417)

Hits:  Ketel Marte (58)

Home Runs:  Ketel Marte (9)

RBI:  Ildemaro Vargas (35)

Stolen Bases:  Geraldo Perdomo (8)

Wins:  Michael Soroka (7)

Saves:  Paul Sewald (14)

ERA:  Brandyn Garcia (1.00)

Batting Average:  Randy Arozarena (.295)

Hits:  Randy Arozarena (61)

Home Runs:  Luke Raley (11)

RBI:  Luke Raley (29)

Stolen Bases:  Randy Arozarena (14)

Wins:  George Kirby (5)

Saves:  Andrés Muñoz (9)

ERA:  Matt Brash (0.00)

Managers:

Arizona Diamondbacks: Torey Lovullo (10th season)

Seattle Mariners: Dan Wilson (3rd season)