The Seattle Mariners host the Arizona Diamondbacks on May 29, 2026. First pitch from T-Mobile Park is scheduled for 10:10 p.m. EDT. The game will be broadcast on SEAM.
The Mariners are priced at -152 to win and at +140 to cover the run-line (-1.5). The Diamondbacks are +128 on the moneyline and -170 to cover +1.5 runs. The total is set at 7.5 runs.
Find my MLB picks and Diamondbacks vs Mariners prediction below, as well as probable pitchers, weather report, and more.
Diamondbacks vs Mariners Prediction
- Diamondbacks vs Mariners Pick: Ketel Marte Over 1.5 Total Bases (+140 — Bet365, Play to +130)
My Diamondbacks vs Mariners best bet is Marte Over 1.5 Total Bases. Make sure to find the best odds by checking our live MLB odds page.
Diamondbacks vs Mariners Odds
| Diamondbacks Odds | ||
|---|---|---|
| Spread | Total | Moneyline |
+1.5 -170 | 7.5 102o / -124u | +128 |
| Mariners Odds | ||
|---|---|---|
| Spread | Total | Moneyline |
-1.5 +140 | 7.5 102o / -124u | -152 |
- Diamondbacks vs Mariners moneyline: Diamondbacks +128, Mariners -152
- Diamondbacks vs Mariners over/under: 7.5 (+102o/-124u)
- Diamondbacks vs Mariners spread: +1.5 (-170), -1.5 (+140)
Diamondbacks vs Mariners Kalshi MLB Odds
Diamondbacks vs Mariners Probable Pitchers
| RHP Zac Gallen (ARI) | Stat | RHP George Kirby (SEA) |
|---|---|---|
| 3-4 | W-L | 5-4 |
| 0.3 | fWAR (FanGraphs) | 1.3 |
| 4.80 / 4.86 | ERA / xERA | 3.54 / 3.35 |
| 4.32 / 4.24 | FIP / xFIP | 3.39 / 3.51 |
| 9.6% | K-BB% | 14.0% |
| 48.9% | GB% | 55.1% |
| .310 | BABIP | .307 |
| 87 | Stuff+ | 101 |
| 109 | Location+ | 113 |
Diamondbacks vs Mariners MLB Betting Preview
Arizona Diamondbacks Betting Preview
The Diamondbacks enter this series having won five straight games and in the midst of a 10-1 tear. Over the last 14 days, they hold a wRC+ of 126 with an OPS of .802, and have struck out just 17.3% of the time while ranking fourth in hard-hit rate.
Corbin Carroll is currently priced as the third favorite to win the NL MVP, as he holds an OPS of .945 while offering excellent range in the field.
After a slow start to the season, Ketel Marte has had an exceptional month of May, as he's slugged .585 with an OPS of 951. Over his last 52 at-bats, Marte has hit .511 and holds an absurd .409 expected batting average and has struck out just 6% of the time.
He continues to be one of the more balanced switch-hitters in baseball and holds an identical .802 OPS versus righties and lefties this season, after offering very neutral splits in 2025.
It continues to feel as though Zac Gallen's best years are behind him, as after pitching to a 4.83 ERA in 2025, Gallen has struggled to an ERA of 4.80 across 54 and 1/3 innings this season.
Even relative to last season his underlying results have regressed, as he holds an xERA of 4.86 and an xFIP of 4.24. Gallen's strikeout-minus-walk rate is down to 9.6%, while his Stuff+ rating has dropped to 87.
Seattle Mariners Betting Preview
Kirby's underlying profile suggested he was among baseball's unluckiest pitchers in 2025, and the 28-year-old righty is living up to his reputation thus far this season with a 3.35 xERA and 3.51 xFIP.
His strikeout-minus-walk rate is actually down considerably since last year while his WHIP is up, while he has still allowed hard contact 42% of the time.
Kirby's form has fallen off to some extent of late, as over his last four outings he's pitched to an ERA of 4.56 and an xERA of 4.46. He's been hard-hit 45% of the time in that span and allowed an xBA of .286.
Seattle's bullpen has remained a strength over the last month, as it has pitched to an ERA of 2.96 with an xFIP of 3.50 and holds the seventh-best strikeout-minus-walk rate in MLB during that span.
The Mariners' offense has seemingly worked its way out of a horrid start to the season, as over the last 30 days they have looked more like the offense we saw in 2025 in hitting to a wRC+ of 103.
Diamondbacks vs Mariners Pick, Betting Analysis
Kirby is a better pitcher than we have seen of late, but he is getting a lot of credit in this matchup with the Diamondbacks' red-hot offense priced at -140 to record fewer than four runs.
While I'm fairly neutral on betting a side or total in this game, backing Marte to record over 1.5 total bases at +140 looks to be a worthy longshot. Marte is in the midst of an incredible run of dominance at the plate, and while his recent BABIP is unsustainable, his recent hard-hit rates and exceptional batting average suggest we can live with the potential for some regression.
We seem to be getting a good price to back one of baseball's hottest bats doing some damage Friday.
Pick: Ketel Marte Over 1.5 Total Bases +140 (Bet365, Play to +130)
