Mariners vs. Athletics Dunkel MLB Picks, Predictions and Prop Bets - April 21

The Seattle Mariners host the Athletics at 9:40 p.m. ET on Tuesday. Luis Castillo (0-1, 5.40 ERA) gets the start for the Mariners, who are 10-14 this season and fourth in the AL West. Jacob Lopez (1-1, 6.38 ERA) is starting for the Athletics, who are 12-11 and first in the AL West.

At home, the Mariners are favored to win on the moneyline (-166) over the Athletics (+140). The game has an over/under set at 7.5 runs.

Mariners vs. Athletics Odds, Game Time

• Game day: Tuesday, April 21, 2026
• Game time: 9:40 p.m. ET
• Location: Seattle, Washington
• Stadium: T-Mobile Park
• Favorite: Mariners (-166)
• Underdog: Athletics (+140)
• Over/under: 7.5

How to Watch Mariners vs. Athletics

• TV Channel: SEAM and NBCS-CA
• Live Stream: Fubo (Watch for free)

Bet now on FanDuel Sportsbook!

Mariners vs. Athletics: Betting the Moneyline

• The Mariners have compiled a 9-11 record in games they were listed as the moneyline favorite (winning 45% of those games).
• The Athletics have won in 10, or 55.6%, of the 18 contests they have been named as odds-on underdogs in this year.
• This season, the Mariners have won three of their six games when favored by at least -166 on the moneyline.
• This year, the Athletics have won three of seven games when listed as at least +140 or better on the moneyline.
• Based on this game's moneyline, the Mariners' implied win probability is 62.4%.
• The Athletics have an implied victory probability of 41.7% according to the moneyline set for this matchup.

Mariners vs. Athletics: Betting the Spread & Total

• The Mariners have combined with their opponents to go over the total 11 times this season for an 11-13-0 record against the over/under.
• The Athletics and their opponents have hit the over in 12 of their 23 games with a total this season.
• The Mariners are 9-15-0 against the spread this season.
• The Athletics are 13-10-0 against the spread in their 23 games that had a posted line this season.