The Seattle Mariners host the Colorado Rockies on September 24, 2025. First pitch from T-Mobile Park is scheduled for 9:40 p.m. EDT; the game will be broadcast on ROOT Sports NW.
The Mariners are on a five-game winning streak and inching closer to the AL West division title. Luis Castillo will get the ball tonight for Seattle against Colorado.
Find my MLB betting preview and Rockies vs Mariners prediction below, as well as probable pitchers, betting trends, injury reports and more.
My Rockies vs Mariners Prediction
- Rockies vs Mariners pick: Under 7.5 (-110)
My Rockies vs Mariners best bet is Under 7.5 total runs in this game. Make sure to find the best odds by checking our live MLB odds page.
Rockies vs Mariners Odds
| Rockies Odds | ||
|---|---|---|
| Spread | Total | Moneyline |
+1.5 +115 | 7.5 -110o / -110u | +240 |
| Mariners Odds | ||
|---|---|---|
| Spread | Total | Moneyline |
-1.5 -140 | 7.5 -110o / -110u | -300 |
Rockies vs Mariners Projected Starting Pitchers
| RHP Tanner Gordon (COL) | Stat | RHP Luis Castillo (SEA) |
|---|---|---|
| 6-7 | W-L | 10-8 |
| 0.9 | fWAR (FanGraphs) | 2.4 |
| 6.00 / 5.51 | ERA / xERA | 3.63 / 4.20 |
| 4.65 / 4.32 | FIP / xFIP | 3.96 / 4.17 |
| 1.46 | WHIP | 1.23 |
| 13.2 | K-BB% | 14.7 |
| 34.2 | GB% | 41.4 |
| 84 | Stuff+ | 96 |
| 106 | Location+ | 106 |
Rockies vs Mariners Preview
Luis Castillo has been on a roll, and with this game meaning so much more to the Mariners, look for him to have another great outing.
The Seattle right-hander has given up just two runs and 10 hits in 18 innings over his last three appearances on the mound. Castillo also has a very strong home split, with a 2.71 ERA at T-Mobile Park this season.
He will face a Rockies offense that ranks dead last in wRC+ this season, with a 75 rating, and has not improved in September, remaining at the same spot with an even worse 64 wRC+. Plus, while away from Coors Field, there is not much to expect from their lineup.
The key to the under hinges on Colorado's pitchers being able to control the Mariners offense.
Tanner Gordon will take the mound for the Rockies, and he has performed much better recently. The right-hander holds a 3.96 ERA across his past seven outings. He's also had back-to-back quality starts, allowing just four earned runs and seven hits over his last 12 innings.
Our Bet Labs system also offers a weather angle, recommending the under.
This system is built for MLB totals where weather and market signals align quietly but consistently toward the under.
It targets regular season games from 2020 through 2025 where the closing total falls between 7 and 10 runs —a middle range that allows for variance but avoids extremes.
This strategy focuses on games with a specific weather profile: wind blowing from left, in from right, or straight in, with speeds between 3 and 15 miles per hour. Combined with moderate temperatures between 30 °C and 70 °C, these environmental conditions help suppress deep fly balls without overly skewing the market.
Line movement also plays a role. The total must have dropped by up to 2.5 runs from open to close, signaling steady downward pressure from sharper bettors. Importantly, the public is not fully behind the under—support remains modest, falling between 1 and 55. This indicates market resistance and helps ensure the number isn’t over-adjusted.
By aligning downward line moves, cooling weather patterns, and under-the-radar betting splits, the system consistently identifies games where offense is subtly but significantly less likely to break out.
Pick: Under 7.5 (-110, BetMGM)
Rockies vs Mariners Betting Trends
