When your rookie year involves mashing a record-breaking 53 home runs, driving in 120 runs, and putting up a 5 WAR season, almost any follow-up can feel like a letdown. In a pandemic-shortened season in 2020, Pete Alonso had a “sophomore slump,” in which he was still 20% better than league average by wRC+. Nonetheless, entering his age 26 season, Alonso was already one of the faces of a 2021 Mets team that had its eyes on playoff contention and expectations were high.
Alas, as we are all too intimately aware, the Mets missed out on the playoffs in 2021 after an epic second-half collapse. But Pete Alonso was decidedly not one of the reasons the Mets fell short this season. In fact, he was one of the few season-long bright spots on the team—one of the only players on an offensively starved roster who hit consistently while also making huge strides on the defensive side of the ball at first base.
Arguably the most important factor in Alonso’s consistency in 2021 was health. Unlike pretty much all the other position players on the Mets in 2021, Alonso had just one short stint on the injured list in late May for a hand issue. At that point, although still above league average, he had been struggling at the plate, like the rest of the roster in the early season. He posted a 119 wRC+ in April with a somewhat concerning 31% strikeout rate. In May until his hand injury, he hit just .233 with a 114 wRC+, but it was later revealed that he had been dealing with the hand injury for quite some time, dating back to when he was hit by a pitch in early May. At the time, the Mets had a whopping 18 players on the injured list.
Injuries plaguing the Mets continued to be a theme of the 2021 season, but Alonso was activated from the injured list on May 31 after being sidelined for the minimum ten days and he never saw the IL again after that. Alonso went on to lead the team in plate appearances in 2021, as well as offensive WAR, OPS+, and bWAR. Fangraphs gives the slight edge to Brandon Nimmo in fWAR and wRC+, but Alonso is a close second in both. It is clear that Nimmo and Alonso were by far the best offensive performers on the team across the whole season, but Nimmo’s season was affected far more by injury, making Alonso the true stalwart at the plate for the 2021 Mets. As the calendar turned to June, Alonso heated up and basically never cooled off. In June he posted a 133 wRC+ and in July that number rose to a 136. And in the second half overall, Alonso put up a 147 wRC+ in 324 plate appearances, lowering his strikeout rate to just 18.5% over that span. When all was said and done, Alonso posted a .262/.344/.519 slash line with a 133 wRC+ in 2021. He hit 37 home runs, drove in 94 runs, and scored 81 runs. He was in the 80th percentile or above in Major League Baseball in exit velocity, hard hit percentage, barrel percentage, and xwOBA, which tells us what we already know to be true: Pete Alonso hits the baseball really damn hard.
While it is very exciting to watch Alonso do what he is best suited to do—mash dingers—an aspect of his 2021 season that cannot go overlooked is how much he improved defensively. He was a liability at first base in both 2019 and 2020, with -5 outs above average (OAA) in both seasons. But he turned that around completely this season and was a instead a positive defender at first base, with +2 OAA in 2021, which was in the 72nd percentile among all players. Of course, this is just one season and defensive metrics can be finnicky; it’s hard to know whether these improvements are sustainable. But the metrics back up what the eye test told us this season; Alonso looked noticeably better at first base, especially ranging both toward the line and in the hole to field grounders. As the potential for a universal DH looms, I think there is no longer any chance that Alonso will be moved off first base in favor of that role (except maybe on occasion)—something that was definitely discussed as a possibility in the past. His defense is something that Alonso has been working very hard to improve, so it was nice to see that hard work pay dividends in 2021.
Because the 2021 season ended so poorly for the Mets, it’s easy to overlook some of the bright spots and individual achievements that came out of this season and many of them were provided by Alonso. His game-tying homer on the 4th of July off Aroldis Chapman sparked a six-run rally that propelled the Mets to victory at Yankee Stadium. As the Mets were scuffling in August, Alonso hit his second career walk-off homer to help the Mets complete a doubleheader sweep of the Nationals and keep hope alive for the time being. In September, Alonso became second-fastest player ever to reach 100 career home runs, doing so against the Marlins in a 9-4 victory in which he hit not just one, but TWO long balls. And of course, Alonso repeated as Home Run Derby champion, joining Ken Griffey Jr. and Yoenis Céspedes as the only players to win back-to-back Derby crowns. “I think I’m the best power hitter on the planet,” Alonso declared. And in terms of raw power, it’s hard to argue otherwise.
Yet somehow, despite all of this, I would argue that Alonso’s 2021 season was underrated—both by Mets fans and by the general baseball media. I think a combination of the disappointment that the 2021 season wrought as a whole and the bar that Alonso set as a rookie in 2019 made it difficult to appreciate Alonso’s everyday excellence this season. It certainly didn’t help that while the Mets were faltering down the stretch, Alonso maintained a positive attitude—something some fans interpreted as a lack of urgency. But really, that’s just who Pete is. He’s a golden retriever of a man that loves hitting baseballs really hard and the sooner we embrace that, the better, in my view. The Mets have something special on their hands in Alonso—a bona fide home grown star that will likely step into a bigger leadership role moving forward with the departure of players like Michael Conforto. The Mets have very few sure things about their roster in 2022, but one of them is Pete Alonso.