The first Diamondbacks trade domino has fallen, as first baseman Josh Naylor is heading to the Seattle Mariners.

The Arizona Diamondbacks traded first baseman Josh Naylor to the Seattle Mariners on Thursday, as first reported by ESPN’s Jeff Passan. It is one of the first major deals of the 2025 MLB trade deadline.

The Seattle Mariners have kicked off MLB Trade Deadline fireworks by swinging a deal for Arizona Diamondbacks star Josh Naylor.

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If the Chicago Cubs had their way, a third baseman, starting pitcher, and reliever would come their way at the trade deadline. While the perfect storm is unlikely, the Cubs should take as aggressive an approach as possible.

The Diamondbacks have shown they would also not like to put Gallen in the discussion. Arizona has been reluctant to make any trades, as the team has hoped it would still remain viable for a playoff berth before the end of July. It looks more unlikely that Arizona will have a chance this season to play in the postseason.

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Pregame analysis and predictions of the Houston Astros vs. Arizona Diamondbacks MLB game to be played on July 22, 2025 on ESPN.