Diamondbacks vs Mariners: How to Make Money Betting This MLB Game on Sunday

Don’t look now, but Merrill Kelly has completely turned around his season. After opening the season with a 9.20 ERA through three starts, Kelly has now lowered his ERA to a 5.25. Can Merrill keep this hot streak going? There’s only one way to find out. 

Elite Pitching Duel Sets the Tone

Bryce Miller anchors Seattle’s hopes with a sparkling 2.25 ERA and 1.00 WHIP across his first three starts of 2026. The right-hander has ramped up velocity and slider usage, generating a 43% whiff rate on the breaking ball. That swing-and-miss arsenal should stifle Arizona’s lineup, especially on the road where the Diamondbacks have shown vulnerability. Merrill Kelly counters with a 5.25 ERA, but he’s delivered four straight quality starts, allowing just seven runs over 29 innings recently. Even on off nights, Kelly induces enough soft contact to keep early damage limited.

Park and Weather Favor Pitchers

T-Mobile Park remains one of MLB’s most pitcher-friendly venues, particularly for right-handers who keep the ball down. With mild temperatures around 60°F, light winds, and the dome likely closed, home runs stay in check. Neither team currently ranks among the league’s top power producers, and recent divisional/interleague play has trended toward lower totals when strong starters are featured.

Offensive Woes

Arizona enters cold off recent games, leaving runners on base and struggling to string hits together against quality arms. Seattle’s lineup has shown life during its winning streak, yet it often relies on solo shots rather than sustained rallies. Both bullpens project as reliable bridges, minimizing late explosions. Historical patterns in similar low-total matchups at this ballpark support a 4-2 or 3-1 type of outcome.

Pitching Dominance

Miller’s dominance plus Kelly’s recent steadiness, combined with a hitter-suppressing environment, screams low-scoring baseball. Expect efficient outings, timely defense, and plenty of zeros on the scoreboard. The under is the best play in this Sunday afternoon clash.