The Seattle Mariners host the Athletics on April 21, 2026. First pitch from T-Mobile Park is scheduled for 9:40 p.m. EDT. The game will be broadcast on SEAM.
The Mariners are favored by -166 on the moneyline and by -1.5 on the run line. The Athletics are +140 on the moneyline and +1.5 on the run line. The total is set at 7.5 runs.
Find my MLB picks and Athletics vs Mariners prediction below, as well as probable pitchers, weather report, and more.
Athletics vs Mariners Prediction
- Athletics vs Mariners Pick: A's ML (+120 or Better)
My Athletics vs Mariners best bet is on the A's to win outright. Make sure to find the best odds by checking our live MLB odds page.
Athletics vs Mariners Odds
| Athletics Odds | ||
|---|---|---|
| Spread | Total | Moneyline |
+1.5 -156 | 7.5 -115o / -105u | +140 |
| Mariners Odds | ||
|---|---|---|
| Spread | Total | Moneyline |
-1.5 +130 | 7.5 -115o / -105u | -166 |
- Athletics vs Mariners moneyline: Athletics +140, Mariners -166
- Athletics vs Mariners over/under: 7.5 (-115o / -105u)
- Athletics vs Mariners spread: Mariners -1.5 (+130 , Athletics +1.5 (-156)
Athletics vs Mariners Pitchers
| Jacob Lopez (LHP, ATH) | Stat | Luis Castillo (RHP, SEA) |
|---|---|---|
| 1-1 | W-L | 0-1 |
| -0.1 | fWAR (FanGraphs) | 0.4 |
| 6.38 / 3.99 | ERA / xERA | 5.40 / 5.60 |
| 6.30 / 6.34 | FIP / xFIP | 3.30 / 4.23 |
| 1.96 | WHIP | 1.80 |
| -1.1% | K-BB% | 11.4% |
| 33.3% | GB% | 40.3% |
| 87 | Stuff+ | 103 |
| 99 | Location+ | 112 |
Athletics vs Mariners MLB Betting Preview
I bet on the Athletics on Monday. It’s back to the well for Tuesday!
I don’t believe Seattle has a big offensive edge over Sacramento. At the same time, my numbers give the Athletics a significant edge in defense and base running.
While Luis Castillo is underperforming (.400 BABIP, 58% strand rate), he always underperforms early in the season. He takes a long time to ramp up, and I believe he simply doesn't perform well in cold weather — unfortunately for him, it’s going to be around 50 degrees during this game.
Regardless, Castillo doesn’t look right. His batted-ball numbers are a mess. Last time out against the Padres, he managed just one whiff on 32 combined sliders and changeups thrown.
Seattle has posted a 116 wRC+ against right-handed pitching this season. The Mariners have posted a 62 wRC+ against left-handed pitching this season. Maybe that gives Jacob Lopez a shot at a decent start.
Athletics vs Mariners Pick, Betting Analysis
I don’t know if the A’s can survive a Lopez start against the Mariners. I also don’t know if the A’s can survive another night with this massive bullpen mismatch.
Regardless, I think this number should be closer to +110 or +115. I am mostly banking on Castillo struggling.
Check out today's full episode of Payoff Pitch:
Pick: A's ML (+120 or Better)
