Jorge Polanco
May 29, 2025
IF/DH
Seattle Mariners
Overview
Polanco signed with the Minnesota Twins as an international free agent in 2009 and made an immediate impact in the system. In his 10-year tenure in a Twins uniform, he compiled a solid .269 batting average with an OPS+ of 111. His breakout season came in 2019, following a 5 year extension signed that spring. That year, he posted a .295 average and an .841 OPS, earning a start at shortstop for the All-Star game. After undergoing his second surgery, Polanco transitioned to second base in 2021, then shifted to third base in 2023. He finished his time with the Twins on a strong note before being traded to the Mariners in January of 2024. However, his debut season in Seattle was a struggle. He recorded career lows in batting average and on-base percentage, while also setting a career high in strikeouts. In October of 2024, Polanco underwent knee surgery, and shortly after, the Mariners declined his option, making him a free agent heading into 2025. Four months later, the Mariners decided to bring him back on a 1 year deal. Now, on a first-place Mariners team, Polanco ranks 2nd in average, slugging, and OPS; he’s tied for 2nd in home runs, sits 3rd in RBIs. League-wide, he ranks in the 97th percentile in xBA, 93rd in xSLG, 91st in Hard-Hit%, 95th in Squared-Up%, and 85th in K%.
2024
2025
Batting Stance
The most significant change that Polanco has made is to his batting stance, an adjustment that has helped him handle offspeed pitches, high-velocity fastballs, and the outer part of the zone. He has also become more aggressive overall, increasing his swing% in all counts and significantly boosting his overall “fast swing” rate. This impressive increase in performance has mainly come from the left side of the plate. This analysis focuses on his performance as a left-handed hitter facing right-handed pitching, where most of his plate appearances occur and where the most notable improvements have come.
Thanks to new metrics from MLB’s Baseball Savant, we can now analyze a batter’s setup in detail, including depth in the box, distance from the plate, stance width, and the degree of stance openness. This is where Polanco has made the most substantial changes. In 2024, from the left side, he stood 37 degrees open, 2nd highest among lefties and 7th among all hitters. This year, he has adjusted dramatically to just 4 degrees open. He also widened his stance, increasing the distance between his feet from 27.6 inches to 32.3 inches. Additionally, he has minimized his leg kick, resulting in a more compact load. These adjustments have helped him address areas of struggle from 2024: namely, hitting offspeed pitches, low-and-away locations, and high-velocity fastballs.
Polanco has increased his swing% on offspeed, leading to a significant jump in SLG on those offerings. In 2024, he struggled particularly with pitches on the outer edge. In 2025, he has greatly improved in that area. This improvement against pitches away, I think, can be partially attributed to the decision to close off his stance.
Polanco also struggled against high-velocity fastballs. In 2024, from both sides of the plate, on all fastballs 96 mph and harder, he had a whiff rate of 23.3% and had a SLG of .431. In 2025, he has whiffed just once on such pitches and holds a .500 SLG. A reduced leg kick has most likely helped him stay ready for high velocity and not get caught late.
Batted Ball Directions
Supporting the idea that he is no longer late on fastballs, Polanco is pulling them at a higher rate, 51.6% in 2025, up from 44.1% in 2024. Conversely, he is going opposite field more often with offspeed: a career-low 9.4% oppo rate in 2024 has risen to 12.0% this season. Since right-handers tend to locate offspeed pitches low and away to left-handed batters, the closed stance and more grounded load appear to help him stay back and drive those pitches the other way.
Another noteworthy trend: Polanco is hitting more ground balls in 2025. Ground ball rate has risen across all pitch types – fastballs (26.5% → 42.4%), offspeed (46.9% → 50.0%), and breaking balls (36.5% → 62.5%) – for an overall increase of 13.4%.
Increased Aggression
Polanco’s aggressiveness at the plate has clearly increased. His overall swing rate has risen from 44.8% to 47.9%, with upticks in nearly every count. His average bat speed has also improved, going from 70.2 mph to 72.0 mph. A “fast swing” is defined as 75 mph or higher, and Polanco has dramatically increased his fast swing rate from 8.6% to 21.1%.
Conclusion
Jorge Polanco’s 2025 performance can be attributed to measurable mechanical and approach-based adjustments. The shift from a 37-degree open stance to just 4 degrees, along with a wider base and reduced leg kick, has coincided with significant statistical improvements across key metrics. His xBA (97th percentile), xSLG (93rd), and Hard-Hit% (91st) reflect real underlying gains, not just surface-level results.
Polanco's swing aggression has increased, his fast swing rate has more than doubled, and his ability to pull fastballs while going opposite field on offspeed pitches shows a refined, situational approach. These changes have also improved his performance against high-velocity fastballs, reducing his whiff rate and increasing his slugging output.
With improved plate coverage, better timing, and increased efficiency in his swing decisions, Polanco has transformed from a declining asset in 2024 into one of the more statistically effective hitters in the league in 2025. His resurgence is quantifiable and sustainable if these trends continue.