Four first base trade candidates for the Mariners
The Mariners may be in the market for a first baseman this summer.
Last year, the Mariners acquired veteran Justin Turner prior to the MLB trade deadline, who would then partner with Luke Raley to transform first base into a productive offensive position over the final third of the 2024 campaign. Eleven months later, it appears Seattle may need to once again go outside the organization to improve at first base.
It seems unlikely that the Mariners will seek a reunion with Turner, who is pictured above. His current club, the Cubs, lead the NL Central division. Plus, the 40-year-old is having the worst season of his distinguished career. With this in mind, I’ve identified first base trade candidates for your review.
It’s unclear whether these players will be made available by their respective teams or if the Mariners would have interest in acquiring any of them. Still, fans enjoy talking about possible trades. So, let’s discuss.
Unless otherwise noted, stats are through June 19 with rankings being based against 160 qualified hitters.
Ryan O’Hearn, LHH - Orioles
Selling points: Just 14 qualified hitters have a higher wRC+ than O’Hearn has. The lone Mariner ahead of him is Cal Raleigh (180) with J.P. Crawford being tied with the eight-year veteran.
Weighted Runs Created Plus (wRC+) quantifies how a hitter’s total offensive value compares with the MLB average after adjusting for park effects. League-average is always 100. Therefore, a wRC+ of 150 means a hitter was 50-percent more productive than the average player. An 80 wRC+ would be 20-percent below average.
O’Hearn’s 16.6-percent strikeout rate is 40th-best. Among Seattle hitters with 150-plus plate appearances, only Jorge Polanco (12.9%) is better. The Sam Houston State alum also boasts an above average walk rate.
Park factors haven’t significantly affected O’Hearn’s overall productivity this season. At Camden Yards, the left-handed hitter has an .896 OPS. Away from Baltimore, it’s an excellent .831.
O’Hearn can play the outfield. This year, he’s started 19 games at first base and has made 15 starts in either right or left field. The former 8th round pick has also served as the Orioles’ designated hitter 36 times. As a first baseman, O’Hearn has accrued three OAA, fifth best among 37 fielders with 50-plus plays at the position.
Outs Above Average (OAA) is a range-based metric that quantifies how many outs a defender has saved compared to the average player. League-average is always ZERO. Source: Baseball Savant
Potential concerns: O’Hearn projects as a platoon player. In 2025, his .619 OPS against southpaws is exactly 300 points lower than what he’s produced against right-handed pitching. This aligns with a 200-point difference in his career platoon splits.
Just to set expectations, O’Hearn isn’t a big bopper. This is an attribute some fans and members of the media value at first base.
O’Hearn’s current wRC+ is about 25 points higher than what he averaged in 2023-24. Perhaps the Dunedin, Florida native’s bat cools over the summer as the temperatures rise.
Thoughts: I don’t subscribe to the philosophy that a first baseman has to be a power hitter. In O’Hearn’s case, his .381 OBP is tied for 14th best in baseball. This kind of on-base ability would go a long way towards lengthening Seattle’s everyday lineup - even if there isn’t a lot of pop in his bat.
Josh Naylor, LHH - Diamondbacks
Selling points: Naylor is having a career year with the 12th-highest batting average in baseball to go with a 30th-best OPS. Avoiding the strikeout has been central to his success. Only 15 hitters have struck out less frequently than the Canadian.
Even though his 24.4 feet-per-second sprint speed is significantly lower than the MLB average (27 feet-per-second), Naylor’s 10 stolen bases leads all first baseman. He would rank third in Seattle behind only Randy Arozarena (14) and Julio Rodríguez (12).
Potential concerns: As with O’Hearn, the left-handed hitting Naylor has been much more effective against righties (.917 OPS) than left-handers (.630 OPS). That said, Arizona doesn’t utilize him in a platoon arrangement.
Naylor has taken advantage of hitter-friendly Chase Field. In his first season as a Diamondback, he boasts a .355 AVG, .409 OBP, and .546 SLG at home with 12 of his 19 doubles coming in Phoenix. Conversely, the 12th overall pick of 2015 has been far less productive on the road (.252 AVG, .303 OBP, .393 SLG).
Thoughts: It’s hard to miss Naylor’s extreme platoon and home/away splits. But a 122 wRC+ since the beginning of the 2022 season suggests to me that the 2024 All-Star could be a valuable offensive contributor.
Rhys Hoskins, RHH - Brewers
Selling points: Hoskins is the lone righty bat on our list, which may make him an appealing option. The eight-year veteran has a respectable .242 AVG, .333 OBP, and .404 SLG against right handers. In fact, his .737 OPS when facing like-handed pitching is noticeably better than any right-handed hitting Mariner with at least 50 plate appearances.
Potential concerns: Hoskins’ 27.7-percent strikeout rate might not fit well on a team that’s struggled to minimize its swing and miss in recent years. Seattle is striking out at a rate that’s close to the MLB average. But adding the Californian to a group of high-strikeout bats that includes Arozarena, Dylan Moore, and Mitch Garver could prove problematic.
Thoughts: Hoskins is an established big-league hitter whose presence could make it easier for manager Dan Wilson to use the left-handed bat of Raley in right field against right-handers. Still, Hoskins’ high strikeout rate is somewhat concerning considering the reputation of T-Mobile Park being a venue that creates strikeouts.
Luis Arráez, LHH - Padres
Selling points: Among active hitters with at least 2,000 plate appearances, Arráez’s .319 career batting average is tops by a large margin. In fact, the only other players with an average better than .300 are Jose Altuve (.305) and Freddie Freeman (.301). Both are on a path leading to Cooperstown.
The left-handed hitting Arráez has struck out just five times in 298 plate appearances, which equates to an MLB-best 1.7-percent strikeout rate.
Potential concerns: Arráez is having a down year with career lows in AVG, OBP, and wRC+. Compounding his current situation, he’s never made loud contact at a high rate.
Arráez’s 15.4-percent hard-hit rate this season is lowest among 197 hitters with 200-plus plate appearances. Moreover, he’s barreled just one of the 279 balls he’s put in play.
Unlike the other hitters we’ve discussed, Arráez doesn’t receive free passes often. The Venezuelan has baseball’s 10th-lowest walk rate.
It’s a relatively small sample, but Arráez’s .247 AVG against left-handers this season is significantly lower than what he’s produced versus right-handed pitchers (.293).
The metrics suggest defense isn’t a strength. Arráez’s minus-8 OAA is worst among first basemen this season. Furthermore, the minus-59 OAA he’s amassed at all infield positions and left field since his 2019 debut ranks last in MLB.
Thoughts: Arráez’s bat-to-ball ability is special and could benefit Seattle’s lineup. However, the team would have to be willing to accept the reality that the vast majority of the 28-year-old’s batted balls won’t be well struck and that his defensive range is suboptimal.
Close, but no cigar
I didn’t profile two relatively well-known names, who fans may have considered possibilities - Nathaniel Lowe and Yandy Díaz. In the case of Lowe, he currently has the worst OBP, SLG, and wRC+ of his seven-year career, while his 27.1-percent strikeout rate is five points higher than it was last year.
As for Díaz, only seven of his 69 games this season have been at first base. Basically, the 33-year-old has morphed into Tampa Bay’s full-time designated hitter. Maybe he’ll be discussed if we broach the topic of the DH spot.
Internal affairs
Perhaps the Mariners view the combination of Raley and Donovan Solano as all that’s needed at first base. After a horrible beginning to the season, the right-hand hitting Solano has a .278 AVG, .350 OBP, .389 SLG, and 119 wRC+ in his last 40 plate appearances dating back to May 10.
Another option could be minor-leaguer Tyler Locklear joining Raley in a platoon. Locklear currently boasts a .839 OPS with Class-AAA Tacoma. The right-handed hitter had a brief audition with the big-league club last year. He wasn’t particularly productive. But the sample was too small to assess then as it is now.
Maybe the Mariners consider using Jorge Polanco as a first base option since rookie Cole Young appears to be settling in at second base, while fellow freshman Ben Williamson and his superb glove defend the hot corner on a daily basis.
It’s worth noting Polanco doesn’t have any professional experience at first base. Therefore, the veteran transitioning to an unfamiliar position mid-season may be a big ask. Then again, adding the switch-hitter to the mix could potentially create greater flexibility at designated hitter and in right field.
Finally
If the Mariners opt to go outside the organization to add a first baseman, O’Hearn would be my top choice followed by Naylor and then Hoskins. That said, it’s reasonable to wonder whether acquiring the defensively-challenged Arráez, who’s also having a subpar season at the plate, would have a positive effect on the roster.
My Oh My…
With how high is seems they are on Canzone, perhaps Raley is the 1B upgrade..? Is Williamson the answer at 3B? Might there be a Suarez reunion?
Hope is the First Baseman with Power.