The Seattle Mariners traded for Arizona Diamondbacks first baseman Josh Naylor Thursday night, effectively kicking off the trade deadline rush. The Diamondbacks received left-handed pitcher Brandyn Garcia and right-handed pitcher Ashton Izzi in exchange. Garcia and Izzi are the Mariners’ 13th and 16th-ranked prospects in their farm systems, respectively, according to MLB Pipeline.
Seattle was repeatedly named as a potential buyer at this trade deadline, with a huge hole at first base. At the same time, Arizona was also tagged as a potential seller as their season remains stuck around the .500 mark. While it’s early to say who would be the big winner in the trade, both teams seem to be getting what they’re looking for.
The Mariners need one thing for their division push, and that is guys who get on base. Of course, Cal Raleigh has been the powerhouse of the offense with a league-leading 39 home runs through 99 games played and a .370 OBP. The other issue is that the offense is spotty, with only two other players, Randy Arozarena and J.P. Crawford, having an OBP over .350.
Meanwhile, Julio Rodriguez has continued to struggle to return to Rookie of the Year form, while Rowdy Tellez isn’t paying off. The team either ranks average or slightly above average with the offense, which isn’t ideal when in a tight wild-card and division race.
Naylor immediately brings contact and even baserunning value to the team, on track for career-highs in batting average and OBP. The first baseman, in fact, automatically has the second-highest OBP and batting average on the team when plugged into Seattle’s lineup. He also has 11 stolen bases, already a career-high, adding another weapon behind Rodriguez and Arozarena.
The first baseman has seen increased contact success when facing all pitches, but hasn’t seen an increase in his slugging average. Naylor’s also registering his highest solid contact and lowest weak contact in his career. Plus, he’s hitting fewer pop-ups and more fly balls. The weird thing is that Naylor hasn’t changed his swing a lot, so it seems his natural talent is finally coming to him.
While Naylor hit 31 home runs last year, don’t expect him to replicate that number unless he has an absolute surge in the last third of the season. His barrel and hard-hit numbers rank in the bottom third of the league, limiting his ceiling. The fact that his strikeout rate is at an all-time low and walk rate is at an all-time high gives him plenty of upside without the power.
In exchange for Naylor, the Diamondbacks netted two pitchers to add to their staff in the next few years. Left-handed pitcher Brandyn Garcia and Right-handed pitcher Ashton Izzi give the farm system a much-needed pitching presence in a team that might be selling off pitchers before July 31. Their highest-ranked pitcher, Cristian Mena, is struggling to get solid footing as his ERA, WHIP, and opposing batting average remain inflated. Daniel Eagan, their 10th-ranked prospect, is still two years away.
Garcia is riding a successful 2024 and respectable 2025 into Arizona, presenting starter-level quality but recently transitioning to the front of the bullpen. In 2024, the left-hander tossed 116 innings with a 2.25 ERA and 134 K, along with surrendering only four home runs. The only downside was his control, with a slightly elevated walk rate but 18 hit batsmen.
As of 2025, Garcia’s seen some regression since transitioning to the bullpen, with a walk rate over four per nine innings and three home runs in only 33.1 innings pitched this season. He’s only hit three batters, but still thrown six wild pitches. While he does have four pitches, Garcia’s changeup is graded as below average. The Diamondbacks will need to spend time developing a fourth pitch for him to become an effective bullpen piece or starter.
The second piece of the Naylor trade, Izzi has struggled in 2025 after posting a somewhat successful 2024 campaign. The 21-year-old posted a 2.85 ERA with 95 strikeouts over 110.2 innings pitched last year, though he struggled with command. His inflated walk rate, 59 walks at a five per nine clip, presents an ongoing challenge for him.
In 2025, Izzi’s command seems to have gotten worse, or trouble adjusting to the high-A level. While his walk rate has decreased, he’s surrendered eight home runs in 47.1 innings pitched, and his hits per nine innings number is also above 10. He is striking out guys at the highest rate of his career, but that’s one of only a few positives he has going for him. Izzi does have a steady three-pitch arsenal, but Arizona will have to work on his execution for him to be a viable piece in the arm department.
It’s going to be a while before we can officially declare who won this trade, but Seattle is getting a valuable player for what they gave away. Naylor is a player who displayed a solid power ceiling, but has expanded his contact abilities this year. At the same time, he’s also stealing bases a lot more often, which can come in handy early or late in games.
The Diamondbacks get two pitchers to place in the bullpen or rotation in due time, but they need work. Garcia might be the more MLB-ready pitcher as of now, which can help if they lose Zac Gallen or Merrill Kelly in a trade. For Izzi, he’s about two to three years away. He has time to develop, so it’s to be seen whether Arizona landed good players.
If you enjoyed this article, subscribe to our newsletter here. Check out Stadium Rant Original shows on our Youtube channel and subscribe! Give our socials Facebook, Twitter, Instagram, TikTok a follow for more great content!
