Phoenix, Arizona, USA; Arizona Diamondbacks first base Josh Naylor (22) celebrates with shortstop Geraldo Perdomo (2) after hitting a walk off grand slam home run against the Seattle Mariners in the eleventh inning at Chase Field. Rick Scuteri-Imagn Images

Josh Naylor Made Arizona Diamondbacks History With Wild Walk-Off Grand Slam

Originally posted on Fastball on SI | By Sam Connon | Last updated Jun 10, 2025 11:40 AM ET

All Josh Naylor needed to do to lift the Arizona Diamondbacks to victory was get the ball out of the infield. He didn't even need a base hit – a deep enough fly ball would do the trick.

The veteran slugger instead opted to go above and beyond.

Arizona had the bases loaded for Naylor when he stepped up to the plate with one out in the bottom of the 11th against the Seattle Mariners on Monday night. He fouled off three pitches in a row, then crushed a high slider from Carlos Vargas.

Naylor sent the ball 387 feet to right-center, clearing the wall for a walk-off grand slam. The D-backs snapped their three-game losing streak with a 8-4 victory, one which earned a spot in the franchise history books.

According to MLB Stats, Naylor's bomb marked the third walk-off grand slam in Diamondbacks history. Ryan Roberts hit the last one on Sept. 27, 2011.

Josh Naylor hits the 3rd #walkoff grand slam in @Dbacks history and first since Ryan Roberts on September 27, 2011. https://t.co/7BuUQUnpse
— MLB Stats (@MLBStats) June 10, 2025

Naylor is now batting .290 with eight home runs, 15 doubles, 44 RBIs, nine stolen bases, an .803 OPS and a 0.9 WAR through 64 games this season. The former All-star first baseman came over from the Cleveland Guardians in a blockbuster trade in December, and he hasn't disappointed yet.

The Diamondbacks and Mariners are set to continue their series at 9:40 p.m. ET on Tuesday.

This article first appeared on Fastball on SI and was syndicated with permission.

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