Oakland, Seattle Make Marginal Infield Upgrades

It’s nearly February and the free agent pool is thinning out. Most of the big names have already flown off the board. By our projections, only five unsigned players forecast to amass at least 1 WAR in the upcoming season, only three of whom are position players. Most teams have already filled out their Opening Day starting lineups; now their focus shifts to improving the fringes of their 26-man roster, searching for a couple of additional wins or insurance in case of injuries. The Mariners and the A’s, two AL West teams with very different outlooks for 2023, each recently made such an addition, inking a veteran to bolster infield depth. Let’s take a look.

Mariners sign Tommy La Stella to a league-minimum deal

Formerly a bench infielder and designated pinch hitter for the Cubs (his league-leading 91 pinch hit appearances in 2018 has not been matched since), La Stella was traded to the Angels with two years of team control remaining for a prospect who never threw a pitch in Chicago’s system. In 2019, he maintained the contact skills and excellent plate discipline that made him a league-average hitter, but he improved in another facet of his game that was emblematic of the juiced ball era. That year, his fly ball rate, which had previously sat around the 20% mark, climbed to 25%; that, combined with a small increase in his pull rate, led to a power break out. Despite lacking traditional power indicators like barrels and a high maximum exit velocity, La Stella made the most of his aerial contact (and the favorable dimensions of Angels Stadium) to post a career-high .486 slugging percentage and hit home runs at a rate of 30 per 600 PA, an excellent mark even during the heightened offensive environment. His absolute refusal to swing and miss played a big part in this as well; his minuscule 8.7% strikeout rate gave him plenty of balls in play, many of which left the yard:

In the shortened 2020 season, La Stella continued his strong performance. His home run rate dipped, possibly due to a midseason trade to Oakland’s unforgiving park dimensions, but he posted the best approach numbers of his career, drawing free passes more than twice as often as he struck out. In his final year before hitting free agency, he set a career high in wRC+ (128). With two consecutive seasons with a .350 wOBA (and a similarly strong xwOBA), multi-positional versatility (he had appearances at first, second, and third), and one of the best approaches in baseball, it’s easy to see why the Giants offered him a backloaded three-year contract worth $18.8 million through the 2023 season.

Unfortunately for the Giants, La Stella’s numbers quickly regressed. His 2021 peripheral stats largely matched up his numbers in Anaheim and Oakland, but he posted a career-low OBP and had just a 93 wRC+ in 242 plate appearances in a bench and platoon role. Still, it seemed possible that he would return to his .342 xwOBA and become an above-average run producer again. But that didn’t happen. La Stella underwent an Achilles surgery in the offseason (which was later revealed to be two surgeries — one for each Achilles) and the lingering effects of injury never seemed to go away. His sprint speed, which had never been great, fell to a career-worst seventh percentile; he hit just two homers in almost 200 plate appearances and walked at the lowest rate of his career. And while he had previously been known as a utility defender, he was worth -4 RAA in just 76 infield innings. In total, his contributions were worth -0.8 WAR. San Francisco cut ties with La Stella a few weeks ago, eating roughly $10 million owed to him.

In signing La Stella coming off a career-worst season, the Mariners are placing a gamble on a return to his pre-injury form, that of an above-average hitter with advanced discipline who at least won’t hurt you in the field or on the basepaths. While Seattle won 90 games last season, their offense ranked 18th in runs scored, and they’ve only made one impact addition to the roster in Teoscar Hernández. RosterResource currently projects AJ Pollock, who had a .284 OBP and 69 wRC+ against right-handed pitching last season, as the full-time starting DH. If his struggles against righties continue, La Stella could take some of his starts there. He could also slide in to give first baseman Ty France the occasional day off, or be a temporary replacement if new second baseman Kolten Wong misses time with injury. Wong hasn’t qualified for the batting title since 2019, and has had numerous short-term injuries in recent memory. Lefty masher Dylan Moore is a solid option, but he’s most valuable in a super-utility role (he started games at seven positions last year), and players on the Mariners 40-man who don’t project to make the Opening Day roster include nine pitchers, three outfielders, a catcher, and a first baseman – a real dearth of infield options. With La Stella, they at least have an infielder with big league experience, someone who should fit fine as the 25th or 26th man on the roster. He almost certainly won’t perform to his 2019-20 level, but La Stella raises the floor slightly for a team with almost no infield depth on the 40-man.

Athletics sign Jesús Aguilar for one year, $3 million

Like La Stella, Aguilar is a formerly very good hitter whose skills have significantly declined recently. But before we address his struggles, let’s talk about what made Aguilar an All-Star and MVP vote-getter in 2018, a season in which he posted a 135 wRC+ and hit 35 homers. A 2007 Cleveland international signee, the hulking slugger was claimed off waivers by the Brewers after struggling in limited big league action with his previous club. After getting consistent playing time at age 27 as the primary first baseman in Milwaukee, he broke out, showing that he could get to his plus raw power in games, hitting plenty of balls in the air, and walking at a high clip while managing his strikeout totals better than many other power hitters. In short, he was your prototypical middle-of-the-order first base/DH type with a good amount of thump in his bat.

Aguilar has spent most of the last three seasons with the Marlins, where he had a 113 wRC+ from 2020-21 as one of the few competent hitters in Miami’s rebuilding lineup. But last year he had the worst full season of his career, bottoming out in exit velocity, barrel rate, and especially his walk and chase rates. His OBP sat at just .281, his WAR at -0.4 WAR, and he showed below-average raw power (measured by maximum exit velocity) for the first time in his career, leading to his release in August. It’s unclear whether this decline was due to Aguilar being intentionally more aggressive at the plate, or if he suffered from unintentional plate vision issues. Hitters around Aguilar’s age do tend to start swinging more as they move along the aging curve, but such a sudden and precipitous drop in walk rate is uncommon:

At his best, Aguilar destroyed pitches in his wheelhouse for homers — he isn’t a contact-oriented bad ball hitter. As such, his increase in out-of-zone swings has led to especially poor results on contact. For his career, Aguilar has a .420 wOBAcon against pitches in the strike zone, but just a .327 mark on out-of-zone pitches. Last year, pitches he had previously taken for balls were popped up or rolled over to shortstop for the easy putout:

The A’s offense can certainly use all the help it can get, as the team ranked last in every triple-slash category last season and gave at least 100 PA to 10 hitters with a lower wRC+ than Aguilar’s mark of 86. That said, the A’s already have a variety of first base and DH options, from Rule 5 pick Ryan Noda to highly regarded prospect Jordan Diaz and fellow rookie Dermis Garcia. Aguilar will likely get a decent chunk of playing time at DH and could possibly squeeze in some time at first if Noda finds an everyday role in the outfield. Like La Stella, Aguilar likely gives a slight boost to this team’s floor, but while a couple of extra wins mean a lot to a Wild Card contender, they’re less important for a team that won just 60 games last season. Still, as long as he’s not taking plate appearances away from guys who could be future everyday fixtures in the A’s lineup, Aguilar should provide a solid veteran bat on a roster full of players trying to make the most of their first big league opportunity.