Seattle Brings Back Josh Naylor

It was just announced that first baseman Josh Naylor is planning on re-signing with the Seattle Mariners on a 5-year deal, pending physical. A trade-deadline addition this past season, Naylor had a career year in 2025 between the Diamondbacks and Mariners, posting a .295 AVG and .816 OPS. He also set career highs with a 128 wRC+ and a 3.1 fWAR. A significant chunk of that production came after he was traded to Seattle, where he put up a .299 AVG, .831 OPS, and 137 wRC+ in his 54 games as a Mariner. Naylor was also a major contributor to Seattle’s 2025 ALCS run, slashing .340 / .392 / .574, good for a .966 OPS in the postseason.

Naylor entered the offseason projected as one of the more valuable bats on the free-agent market. Baseball Savant credited him with a +21 Batting Run Value in 2025, 7th among batters hitting free agency. He has become one of my favorite players to watch, and it's no surprise Seattle wanted him back. In my opinion, he’s been one of the league’s most underappreciated impact players. What makes Naylor so special is the rare combination of great bat-to-ball skills, above average power, and an elite strikeout rate. 

Since 2021, the following list highlights hitters with at least 2,000 PA over that span who posted a slugging percentage of .450 or higher and a strikeout rate of 16.0% or lower.

If we lower the threshold to 1,500 plate appearances, one name joins the group: Vinnie Pasquantino, who has been similarly overlooked with a .456 SLG and 13.5% strikeout rate. In an era where power is often willingly exchanged for swing and miss, what Naylor is doing is incredibly valuable. Another Seattle slugger hitting free agency is Eugenio Suárez, whose 49 home runs and .526 SLG jump off the page. However, I don’t think he’ll generate the same level of buzz he had at the deadline. His strikeout concerns remain significant, and he looked somewhat exposed after the move to T-Mobile Park.

Away from the plate, Naylor pulled off one of the most surprising feats of the season, recording 30 stolen bases. Despite ranking in the 3rd percentile in sprint speed (24.4 ft/s), he became just the 2nd first baseman since 2000 to reach 30 SB, joining Paul Goldschmidt’s 32 in 2016. Naylor and José Ramírez were the only corner infielders to reach 30 steals in 2025. This improvement is staggering for a player who had only topped 10 steals once (10 in 2023). A lot of that comes down to Naylor’s baseball IQ and instincts. 

Looking at Baseball Savant’s Basestealing Leaderboards, Naylor consistently gets great jumps. Savant defines Lead Distance Gained as “Distance in feet a runner has advanced from the start of delivery to pitch release.” In other words, it measures how quickly a runner can react and burst before the ball leaves the pitcher’s hand. Naylor averaged 16.8 feet gained on his stolen base attempts, that is the 2nd most of the 70 players who had at least 15 stolen bases in 2025. It’s a great example of why being an effective baserunner isn’t all about speed. He is also very selective with his attempts, only running on 2.7% of the times he reached base. Among the 21 players who stole 30 bags, only 4 had a lower Stolen Base Attempt percent. Even with the conservative approach, he finished with +15 Net Bases Gained, which is defined as bases gained (stolen base / balk) minus outs created (caught stealing / pickoffs), good for 15th in the league. 

Defensively, Naylor has graded out as around league average. He posted 2 Outs Above Average which lands in the 80th percentile, but his -1 Defensive Runs Saved and a Savant Fielding Run Value of -1 this past season land slightly below league average (45th percentile). 

Although the total dollar amount of the deal is still unannounced, most public projections correctly had him at the five year mark. MLBTradeRumors predicted 5 years and $90 million ($18M AAV), while Spotrac estimated 5 years and about $75 million ($15M AAV). Still only 28 years old, with no qualifying offer attached, Naylor would have been one of the more attractive first-base options, in competition with Pete Alonso. With a market that doesn’t have a great recent history of loving first basemen, I’m not super surprised that the quick fan favorite decided to return to Seattle. 

Something to keep an eye out for is how Pete Alonso’s market will react given he is really the only proven primary first baseman with MLB experience left. Of course Munetaka Murakami, coming from Japan is making headlines but it's been tough to get a feel for what his market will look like. Despite his obvious hulk-like power, there are major strikeout and whiff concerns. So while there are still options out there for teams in need of a first baseman, Naylor being removed from that list may shift how this offseason unfolds.