Oakland Athletics vs Seattle Mariners Prediction 4/20/2026 Today’s MLB Picks

In this article, we will formulate an Athletics vs Mariners Prediction for this MLB matchup on Monday, April 20th in the opening game of this series. Let’s take a look at the prediction for this MLB matchup.

Seattle Mariners Preview

The Seattle Mariners have a 10-13 record this season and are sitting in the fourth place of the AL West. They have a 9-5 home record and are coming off a 5-2 home win against the Rangers. Their previous three games were a 7-3 home win and a 0-5 home loss against the Rangers, and a 2-5 road loss to the Padres.

The Mariners have a .216 batting average this season, .320 OBP and .347 Slugging percentage. Seattle’s pitching staff has a 3.22 ERA and 1.16 WHIP. Luke Raley is the team’s best hitter with a .313 batting average, also leading the team in RBI with 13 and adding a team‑high 5 home runs.

Emerson Hancock (R) is the projected starting pitcher for the Mariners, and he has a 2-1 record, 2.28 ERA and 0.76 WHIP.

Check out Monday’s game between the Braves and Phillies. 

Athletics Preview

The Athletics have a 11-11 record this season and are sitting in the first place of the AL West. They have a 6-6 away record and are coming off a 4-7 home loss against the White Sox. Their previous three games were a 7-6 home win and a 2-9 home loss against the White Sox, and a 6-9 home loss against the Rangers.

The Athletics have a .228 batting average this season, .310 OBP and .362 Slugging percentage. Oakland’s pitching staff has a 4.82 ERA and 1.50 WHIP. Shea Langeliers is the team’s best hitter with a .310 batting average, also leading the team in RBI with 12 and adding a team‑high 6 home runs.

J.T. Ginn (R) is the projected starting pitcher for the Athletics, and he has a 0-0 record, 3.31 ERA and 0.98 WHIP.

Athletics @ Seattle Mariners Betting Trends: April 20, 2026

• Probable Starting Pitcher: Emerson Hancock      Record this season: 2-1      ERA: 2.28
• Home Record: 2-0
• Last 5 against Athletics: 0-0

Why the Seattle Mariners will win

• The home team has won 14 of the Mariners’ last 15 games.
• The Athletics have lost each of their last five games at T-Mobile Park against teams that held a losing record.
• The Athletics have failed to cover the run line in seven of their last eight games against teams that held a losing record.
• The Mariners have covered the run line in each of their last six Monday games.
• The Athletics have trailed after 3 innings in seven of their last eight games against opponents that held a losing record.
• The Mariners have won the first inning in eight of their last nine home games against AL West opponents.
• The Athletics have trailed after 5 innings in each of their last four games against American League opponents that held a losing record.

• Probable Starting Pitcher: J.T. Ginn      Record this season: 0-0      ERA: 3.31
• Road Record: 0-0
• Last 5 against Mariners: 0-0

Why the Athletics will win

• The Athletics have won each of their last five games as road underdogs.
• The Mariners have lost eight of their last nine night games after playing the previous day.
• The road team has covered the run line in 11 of the Athletics’ last 12 games.
• The Mariners have failed to cover the run line in seven of their last eight night games following a win.
• The Athletics have led after 3 innings in each of their last four night games against AL West opponents that held a losing record.
• The Athletics have won the first inning in three of their last four night games against AL West opponents that held a losing record.
• The Athletics have led after 5 innings in each of their last four night games against AL West opponents that held a losing record.

Total Runs Facts

• Eight of the Athletics’ last nine road games after playing the previous day have gone UNDER the total runs line.
• Five of the last six games between the Athletics and Mariners have gone UNDER the total runs line.
• The ‘Inning 1 OVER 0.5 runs’ market has hit in each of the Mariners’ last nine home games.
• The ‘Inning 1 OVER 0.5 runs’ market has hit in eight of the Athletics’ last nine road games against AL West opponents.

Seattle Mariners Player Prop Facts

• Cal Raleigh has hit at least one home run in four of his last eight home appearances against the Athletics after playing the previous day.
• Victor Robles has recorded at least one hit in seven of his last eight home appearances against AL West opponents.
• Luke Raley ranks 5th amongst qualified players for Slugging Percentage (.627) this season.

Athletics Player Prop Facts

• Jeff McNeil has recorded at least one hit in nine of his last 10 appearances against the Mariners.
• Brent Rooker has hit a home run in three of the Athletics’ last five games against the Mariners.
• Shea Langeliers ranks T10th in the league in Hits (26) this season.

Matchup/League Facts

• The Mariners rank 1st in the league for walks allowed this season (54).
• The Mariners rank T2nd in the league for ERA this season (3.22).
• The Athletics rank 29th in the league for walks allowed this season (115).
• The Athletics rank T6th in the league for triples this season (3).

Athletics vs Mariners Prediction

The Mariners are 5-3 in their last 8 meetings against the A’s and are 3-1 in their last 4 meetings in Seattle. Under is 5-1 in their last 6 meetings.

In this Athletics vs Mariners Prediction, the Mariners are coming as -160 home favorites. Both teams have been mediocre this season but the Mariners have back-to-back wins, while the A’s are 1-3 in their last 4. Both pitchers have been excellent this season with a combined 5.59 ERA and sub-1.00 WHIP and both teams average 8.1 runs per game combined, so I don’t expect a high-scoring game today. Take the under 8.5 runs in this one.

Nikos Lagouretos's Pick: Under 8.5