Seattle Mariners vs Arizona Diamondbacks Prediction, Odds and Picks for Monday, 06/09/25

Emerson Hancock is the weakest starting pitcher in the Seattle Mariners’ starting rotation, and he is a weak spot I have been attacking this season. Monday’s matchup with the Arizona Diamondbacks is a tough one on paper for Hancock as his weaknesses are exposable against a lineup as potent as Arizona’s. The Diamondbacks thrive against right-handed pitching, leading baseball in wOBA against righties since May 1. Hancock is a low-whiff pitcher who struggles to generate outs without contact being made, and the Diamondbacks are a rather strikeout-averse lineup.

Merrill Kelly is easily my preferred starting option in this matchup as the veteran right-hander enters this game following 7 scoreless frames in a tough matchup with the Braves. Kelly has been lethal at home this season, something that has been true for several years now, and he gets a Mariners lineup that ranks within the bottom 5 in wOBA against righties since May 1. The Mariners have been better against southpaw pitching and I expect Kelly to tame their bats in this spot.

Mariners vs Diamondbacks prediction: Diamondbacks ML (-165) available at time of publishing. Playable to -170 odds.

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