Josh Naylor Becomes the First D-back Dealt Ahead of the Deadline

For the second straight season, the Arizona Diamondbacks make the first significant trade in the final week ahead of Major League Baseball’s trade deadline. Last year, they acquired A.J. Puk to fortify their bullpen; this year, they sent first baseman Josh Naylor to the Seattle Mariners for a pair of pitching prospects.

The deal was first reported by Jeff Passan of ESPN.

D-backs Under Review is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber.

It is the fifth major deal between the D-backs and Mariners since Mike Hazen took over baseball ops in November 2016. Other notable players Arizona has acquired from the Mariners include Ketel Marte, Taijuan Walker, Paul Sewald, Mike Leake, and Eugenio Suárez.

Why the D-backs Traded Josh Naylor

It comes as no surprise that Naylor is the first one to go. I mentioned in a previous post about it being clear the team should not buy that the team should look to move him and Zac Gallen first at the deadline. Naylor’s 31-homer power did not translate after a move to Arizona, even though he’s driven in a respectable 59 runs.

Despite the productive line serving as the D-backs’ cleanup hitter, there are some concerning trends involving his underlying metrics. His xBA (.288) and xSLG (.448) are right in line with his season numbers (.292 and .447). However, there’s a significant decline in hard-hit rate, barrel rate, and chase rate compared to 2024.

• 2024: 40.9% Hard-Hit Rate (54th percentile), 8.4% barrel% (55th), 32.2% chase rate (25th)
• 2025: 40.1% Hard-Hit Rate (37th percentile), 6.6% barrel% (33rd), 34.8% chase rate (12th)

It may be a case of chasing out of the zone and making more contact as a result. Perhaps it was the pressure of trying to secure a long-term contract on top of playing for a team with expectations that they would contend. The results of that approach certainly didn’t hurt the D-backs’ chances, as they’d happily take a 124 OPS+ bat in the middle of their lineup.

It was going to be a difficult decision to extend a $21-22 million qualifying offer despite a track record of being a solid hitter the past three seasons. Despite a solid .277/.341/.465 slash line, good for a 124 OPS+, he’s been worth just 4.8 bWAR. Most of that value is taken away by the glove, with -10 fielding runs and -20 positional runs. His defense has been problematic, especially for a team that’s had strong first base play for the previous 13 seasons between Paul Goldschmidt and Christian Walker (6 Gold Gloves).

Analyzing the Return for Naylor

Garcia and Izzi rank 13th and 16th in MLB Pipeline’s midseason Top 30 list for the Seattle Mariners. However, it’s important to note that prospect rankings are not to be taken as gospel, but rather one evaluator’s opinion based on the information they have at the time.

The organization views Garcia as a reliever, as reported by Arizona Sports insider John Gambadoro. As a lefty that can touch upper 90s with heavy sinking action (97.1 MPH, 3.3” induced vertical break, 15.4” arm-side run), a hard slider (89.6 MPH, 1.3” iVB, 2.1” glove-side sweep) and a sweeping slider (85.2 MPH, -0.9” iVB, 15.4” glove-side sweep), he has the potential to become a long-term difference maker.

He seems like the perfect candidate to grow into A.J. Puk’s intended role as the top lefty in the bullpen. He has since been optioned to Triple-A Reno, per the club, so he will continue to develop in the minor leagues but could be a September call-up candidate since he’s already on Arizona’s 40-man roster.

While the sample size is very limited in Triple-A (148 total pitches), he’s held lefties to a .200 average and a .200 slugging percentage in 12 PA. Righties are hitting .304 with a .318 slug in 25 PA. There isn’t much to draw from here when it comes to projecting him as a potential big league reliever.

Going into the start of 2026, the D-backs could have a potential trio of lefties in their bullpen between Kyle Backhus, Andrew Saalfrank, and Garcia.

Izzi is more of a long-term upside play, with the phrase “lottery ticket” being the common vernacular. A 4th rounder in the 2022 draft who signed a $1.1 million bonus out of high school, he’s spent the entire season with High-A Everett. In 12 starts with Everett, spanning 47.1 innings, he has a 5.51 ERA with a 24.9% strikeout rate and a 9.7% walk rate.

Most likely, he will continue to develop as a starter with Hillsboro to finish out the year and could be a candidate for the Arizona Fall League. He missed about four weeks this season with an oblique strain.

Marquee Sports Network analyst Lance Brozdowski profiles the two pitchers in the deal.

Who Takes Over for Naylor?

Mentioned in another previous post about who could benefit from the team selling at the deadline, Tristin English is the obvious call-up candidate for Naylor. That move has since been announced by the D-backs on X.

Whether or not they decided to move Naylor, the position still had uncertainty going into 2026. The D-backs could opt for a Pavin Smith/Tristin English platoon, which they’ll likely finish the 2025 season with, then go into the market for a full-time DH as one possibility. The Angels’ Taylor Ward would make a lot of sense for the club in an offseason trade.

What’s Next?

There is a possibility that the D-backs will also trade Eugenio Suárez, Merrill Kelly, Zac Gallen, Jalen Beeks, Randal Grichuk, and possibly Shelby Miller. Francys Romero reports that the team could trade as many as five to six more players.

The Mariners are reportedly still pursuing Suárez as their top priority, per Adam Jude of The Seattle Times. Given the history between the two clubs, I wouldn’t rule out another deal.

D-backs Under Review is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber.

D-backs Under Review is Michael McDermott’s publication for deep analysis dives, game coverage, prospect coverage, and breaking down the biggest news topics involving the Arizona Diamondbacks. Michael has been writing about the D-backs since the 2015 season, with stops at AZ Snake Pit, Diamondbacks On SI, Venom Strikes, and Burn City Sports. He has covered over 40 MLB games at Chase Field and the Arizona Fall League.