The deafening quiet of this year’s July trade market was disturbed on Thursday night with the announcement that the Seattle Mariners were acquiring first baseman Josh Naylor from the Arizona Diamondbacks. Naylor has provided more than respectable offense for the Snakes this year, hitting .292/.360/.447 with 11 homers, good for a 123 wRC+ and 1.4 WAR. Heading to the desert in return are two minor league pitchers, lefty Brandyn Garcia and righty Ashton Izzi.
While the Diamondbacks have generally disappointed in 2025, little of the fault can be placed at Naylor’s feet. The team expected to compete in 2025, but lost Christian Walker to the Astros in free agency, so the hope was that Naylor would fill the hole for a year before hitting the open market himself. He was never going to be an elite defensive first baseman like Walker, but the expectation was that he would at least provide a similar level of offense. Naylor is likely to fall well short of his career-high 31 homers from 2024, but he’s compensated for that by adding nearly 50 points of batting average, meaning his 123 wRC+ is actually slightly higher than his 119 mark from last season.
If the season ended today, the Mariners would make the playoffs as the second AL Wild Card, and the five-game separation between them and the division-leading Astros is not an insurmountable distance. Houston’s edge in the AL West seems even smaller when you consider how much of its lineup is currently out hurt. The injured quartet of Yordan Alvarez, Isaac Paredes, Jeremy Peña, and Jake Meyers would represent a huge chunk of any team’s offensive value. First base has been a particular source of trouble for the M’s this year, with their first basemen ranking in the bottom third in baseball with a combined 0.4 WAR. The original plan had been for Luke Raley to get the lion’s share of the playing time at first, mostly against righties, with fill-ins around him to take care of the southpaws. However, injuries to Mitch Haniger and Victor Robles thinned out Seattle’s corner outfield and DH depth and pushed Raley mostly to right field. As a result, the team was forced to give a lot of playing time to Rowdy Tellez; he posted an execrable .249 on-base percentage with the Mariners before they dropped him in June.
Naylor is not a superstar, so naturally, his acquisition doesn’t dramatically change the face of the AL West race. After last night’s win over the Angels, ZiPS gave the Mariners a 76% chance to make the playoffs and a 24% probability to win the division. These numbers would be 72% and 21% without the trade.
So, what’s the cost for their new first baseman? Neither Garcia, nor Izzi was torching up the prospect lists, but then again, Naylor is a free agent after the season, making this trade is a pure short-term rental. The 25-year-old Garcia has already made a brief major league debut, and since I don’t believe the Diamondbacks are going to go full rebuild, that has a lot of allure over the compensation draft pick they would have gotten if they’d held onto Naylor and he’d signed elsewhere this offseason. Garcia is a hard-throwing lefty sinkerballer with a three-quarters delivery who predictably induces a lot of grounders. My colleague Eric Longenhagen gave him a 40+ FV when Seattle’s top prospects list was published last month.
The ZiPS projections see Garcia as a solid, though unspectacular, mid-bullpen arm with at least some upside.
ZiPS Projection – Brandyn Garcia
| Year | W | L | ERA | G | GS | IP | H | ER | HR | BB | SO | ERA+ | WAR |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026 | 3 | 3 | 4.22 | 57 | 0 | 53.3 | 48 | 25 | 5 | 22 | 45 | 98 | 0.0 |
| 2027 | 3 | 3 | 4.10 | 56 | 0 | 52.7 | 47 | 24 | 5 | 21 | 45 | 101 | 0.1 |
| 2028 | 3 | 2 | 4.08 | 55 | 0 | 53.0 | 46 | 24 | 4 | 21 | 45 | 102 | 0.2 |
| 2029 | 3 | 2 | 3.92 | 46 | 0 | 43.7 | 39 | 19 | 4 | 17 | 37 | 106 | 0.1 |
| 2030 | 2 | 2 | 4.06 | 40 | 0 | 37.7 | 33 | 17 | 3 | 15 | 32 | 102 | 0.1 |
| 2031 | 2 | 1 | 4.06 | 33 | 0 | 31.0 | 27 | 14 | 2 | 12 | 26 | 102 | 0.1 |
ZiPS 2026 Percentiles – Brandyn Garcia
| Percentile | ERA+ | ERA | WAR |
|---|---|---|---|
| 95% | 128 | 3.23 | 0.7 |
| 90% | 122 | 3.40 | 0.6 |
| 80% | 114 | 3.65 | 0.4 |
| 70% | 107 | 3.88 | 0.2 |
| 60% | 102 | 4.06 | 0.2 |
| 50% | 98 | 4.22 | 0.0 |
| 40% | 93 | 4.43 | -0.1 |
| 30% | 90 | 4.59 | -0.2 |
| 20% | 86 | 4.83 | -0.3 |
| 10% | 77 | 5.36 | -0.6 |
| 5% | 71 | 5.82 | -0.9 |
As a 21-year-old in High-A ball, Ashton Izzi has more developing to do than Garcia, but even with decidedly mixed results, the righty showed enough upside for Eric to also give him a 40+ FV. According to Eric, Izzi boasts a four-seamer that sits around 94 mph with solid movement. He gets “near elite” extension with his fastball, but it doesn’t generate many whiffs. Izzi also has a usefully average two-seamer, Eric says, as well as a sweeper and a cutter; the sweeper is a big swing-and-miss pitch for him. His changeup is mediocre, and Eric is concerned that Izzi will struggle to develop a good weapon to wield against lefties. Overall, per Eric, if Izzi can clear his developmental hurdles, he can make the majors as a starter.
In all, I think getting two real prospects, one who can impact the parent club immediately, is an absolutely fair return for Naylor. The Mariners have only two playoff wins over the last two decades, and now is the time to go all-in to add to that total. Their offense is better this season than in previous years, but they still needed to fill their hole at first base, and Naylor represents a major upgrade over what they had before.
