The first season right-hander Pablo López spent with the Minnesota Twins was an unqualified success. Not long after bringing him from Miami in a trade for Luís Arráez in January 2023, the Twins agreed with López on a $73.5 million contract extension that bought three years of free agency. Not long after signing, López made the AL All-Star team.
Come October, with López on the mound for two successful starts, the Twins won their first postseason series since 2002.
Those happy results failed to repeat in 2024, with the club fading under .500 in the AL Central standings and missing the playoffs, and López regressing individually.
Will he regain his All-Star form in 2025 and return to his place among the most valuable pitchers in the league, or will López repeat a performance that was OK, but also not all that he promised the season before?
Is López going to get Better or Worse?
López's results fell off despite throwing one of the most valuable pitches in Major League Baseball: his four-seam fastball. Throwing harder than ever, López in '24 earned 15 runs of pitch value, per Statcast, with his four-seamer.
Only 10 other four-seamers earned more, and only 23 pitches overall were more valuable across the league.
And he threw his four-seamer a lot: 1,206 times, which accounted for 40% of López's arsenal. Batters responded with a .211 batting average and .356 slugging against. Despite having the most effective pitch of his career at his disposal, López in 185 1/3 innings posted a 4.08 ERA, his highest since 2019, and 22 points higher than his career mark through his first six seasons.
López's issues came with his other pitches, none of which finished with a positive run value. His sweeper (minus-1) came closest, but was vulnerable because of eight home runs allowed. López's sinker (minus-8 RV) went particularly cold, losing 14 runs of value over 2023 (though he only threw 230 of them).
Batters hit .406 with a .609 slugging percentage against the sinker. López's changeup and curveball were both minus-4 on the run value scale.
Contrast those results with ones from the season before (not only the sinker), and it becomes clearer how López slipped. In '23, he threw four pitches that had a positive run value, with a fifth (his curve) finishing neutral.
Being more effective against the league came easier because of a varied arsenal. As a result of not having one in 2024, López didn't strike out as many, he allowed a few more hard-hit balls (including home runs), and he put himself in position to be victimized a little more by bad luck.
Generally, he left too many pitches over the heart of the plate, he gave up too many barrels, and he didn't get batters to swing and miss as much. His sinker didn't sink enough, and his sweeper wasn't all that sweeping. He needs more horizontal movement.
Understanding why López's results regressed is easier than fixing his problems and getting him back to the All-Star Game, but it's possible he was on his way to doing that in late 2024.
After posting a 5.19 ERA in his first 19 starts, López was better in the second half (2.77 ERA) despite a lower strikeout rate and higher walk rate. His changeup gained effectiveness and his curve improved from poor to neutral.
Simply being a little positive with multiple pitches over an entire season would do wonders for López's results.
And it's not like he missed with his other pitches by a mile. His expected batting average with his sweeper was 42 points lower, and his slugging percentage was 105 points lower. His expected stats with his sinker weren't good (.333 xBA and .537 SLG), but they were a lot better than what happened (.406/.609). López definitely lacked some luck; his combined BABIP the past two seasons (.313) was 21 points higher than in his first 510 career innings.
The early signs look good regarding López fastball, which he's been throwing 95-96 mph according to Spring Training reports from Fort Myers.
If he can regain the past effectiveness of his sweeper, build on the recent improvement in his changeup, and/or eliminate the worst sinkers of his repertoire and make them neutral at worst, López will have varied his offerings enough to keep opposing batters on their heels.
It would put the Twins in a better position to win more of his starts in 2025 and, hopefully, return to the playoffs.