Mariners vs Athletics Prediction, Odds, Moneyline, Spread & Over/Under for April 21

Odds updated as of 5:12 a.m.

On Tuesday in MLB, the Seattle Mariners are playing the Athletics.

Before checking out the MLB betting lines on FanDuel Sportsbook, we've got you covered, in terms of the vital information regarding this game.

Mariners vs Athletics Game Info

• Seattle Mariners (10-14) vs. Athletics (12-11)
• Date: Tuesday, April 21, 2026
• Time: 9:40 p.m. ET
• Venue: T-Mobile Park -- Seattle, Washington
• Coverage: Mariners.TV and NBCS-CA

Mariners vs Athletics Odds & Moneyline

• All MLB odds, betting lines and prop bets are available on FanDuel Sportsbook.
• Moneyline: SEA: (-172) | OAK: (+144)
• Spread: SEA: -1.5 (+125) | OAK: +1.5 (-150)
• Total: 7.5 -- Over: (-110) | Under: (-110)

Mariners vs Athletics Probable Starting Pitchers

Probable Pitchers: Luis Castillo (Mariners) - 0-1, 5.40 ERA vs Jacob Lopez (Athletics) - 1-1, 6.38 ERA

The Mariners will look to Luis Castillo (0-1) against the Athletics and Jacob Lopez (1-1). Castillo and his team are 1-3-0 ATS this season when he starts. Castillo's team has been victorious in 33.3% of the games he's started as the moneyline favorite with a record of 1-2. The Athletics are 2-2-0 against the spread when Lopez starts. The Athletics have a 2-2 record in Lopez's four starts this season when they were the underdog on the moneyline.

Mariners vs Athletics Prediction & Pick

All MLB win probability predictions and picks are according to numberFire.
Prediction: Mariners win (59.7%)

Mariners vs Athletics Moneyline

• The Mariners vs Athletics moneyline has the Mariners as a -172 favorite, while the Athletics are a +144 underdog on the road.

Mariners vs Athletics Spread

• The Mariners are 1.5-run favorites on the runline against the Athletics. The Mariners are +125 to cover, while the Athletics are -150 to cover.

Mariners vs Athletics Over/Under

• The over/under for the Mariners versus Athletics contest on April 21 has been set at 7.5, with -110 odds on the over and -110 odds on the under.

Bet on Seattle Mariners vs. Athletics on FanDuel today!

Mariners vs Athletics Betting Trends

• The Mariners have won in nine, or 45%, of the 20 contests they have been named as odds-on favorites in this year.
• This season, the Mariners have come away with a win three times in five chances when named as a favorite of at least -172 or better on the moneyline.
• The Mariners and their opponents have hit the over in 11 of their 24 games with a total this season.
• The Mariners are 9-15-0 against the spread in their 24 games that had a posted line this season.
• The Athletics are 9-8 in games they were the underdog on the moneyline (winning 52.9% of those games).
• The Athletics have a record of 2-3 when they have played as a moneyline underdog with odds of +144 or longer (40%).
• The Athletics have combined with their opponents to go over the total 12 times this season for a 12-11-0 record against the over/under.
• The Athletics have collected a 13-10-0 record ATS this season.

Mariners Player Leaders

• Randy Arozarena leads Seattle with an OBP of .386, plus a team-best slugging percentage of .407. He's batting .279 on the season.
• Among the qualifying batters in baseball, his batting average ranks 46th, his on-base percentage ranks 23rd, and he is 77th in slugging.
• Cole Young is hitting .244 with two doubles, a triple, two home runs and 11 walks. He's slugging .366 with an on-base percentage of .340.
• Among qualifying batters, he ranks 91st in batting average, 78th in on-base percentage and 115th in slugging percentage.
• Young has picked up a hit in five games in a row. In his last five games he is hitting .353 with three walks and two RBIs.
• Dominic Canzone has 14 hits this season and has a slash line of .275/.333/.569.
• Canzone enters this game with three games in a row with at least one hit. During his last five outings he is batting .438 with three doubles, a home run, a walk and five RBIs.
• Luke Raley leads Seattle with 21 hits, batting .304 this season with 10 extra-base hits.

Athletics Player Leaders

• Shea Langeliers has a slugging percentage of .584 and has 27 hits, both team-best numbers for the Athletics. He's batting .303 and with an on-base percentage of .367.
• Including all qualified hitters in the big leagues, he ranks 21st in batting average, 45th in on-base percentage and 12th in slugging percentage.
• Tyler Soderstrom has seven doubles, a triple, two home runs and 11 walks while hitting .213. He's slugging .382 with an on-base percentage of .300.
• He ranks 138th in batting average, 127th in on-base percentage and 104th in slugging percentage in the majors.
• Jacob Wilson is batting .263 with three doubles, two home runs and a walk.
• Nick Kurtz's .420 on-base percentage paces his team.

Mariners vs Athletics Head to Head

• 4/20/2026: 6-4 OAK (Favorite: Mariners, Spread: -1.5, Total: 8, Favorite Moneyline: -142, Underdog Moneyline: +120)
• 8/24/2025: 11-4 SEA (Favorite: Mariners, Spread: -1.5, Total: 7.5, Favorite Moneyline: -180, Underdog Moneyline: +152)
• 8/23/2025: 2-1 OAK (Favorite: Mariners, Spread: -1.5, Total: 8, Favorite Moneyline: -172, Underdog Moneyline: +144)
• 8/22/2025: 3-2 SEA (Favorite: Mariners, Spread: -1.5, Total: 8, Favorite Moneyline: -215, Underdog Moneyline: +180)
• 7/30/2025: 5-4 OAK (Favorite: Mariners, Spread: -1.5, Total: 9.5, Favorite Moneyline: -154, Underdog Moneyline: +130)
• 7/29/2025: 6-1 OAK (Favorite: Mariners, Spread: -1.5, Total: 10.5, Favorite Moneyline: -110, Underdog Moneyline: -106)
• 7/28/2025: 3-1 SEA (Favorite: Mariners, Spread: -1.5, Total: 10.5, Favorite Moneyline: -120, Underdog Moneyline: +102)
• 5/7/2025: 6-5 SEA (Favorite: Mariners, Spread: -1.5, Total: 9.5, Favorite Moneyline: -138, Underdog Moneyline: +118)
• 5/6/2025: 5-3 SEA (Favorite: Athletics, Spread: -1.5, Total: 10, Favorite Moneyline: -120, Underdog Moneyline: +102)
• 5/5/2025: 7-6 OAK (Favorite: Mariners, Spread: -1.5, Total: 9, Favorite Moneyline: -116, Underdog Moneyline: -102)

Sign up for FanDuel Sportsbook and FanDuel Daily Fantasy today!