Remember when New York Yankees slugger Aaron Judge was mired in the slump to end all slumps? Or before that, when it appeared no park could contain his titanic blasts? The larger-than-life Judge has a tendency to take us to the extremes, for good and for bad — and sometimes both at once.

So it was against the backdrop of all that on Monday when Judge reminded us just how insane his rookie season has been, through all the peaks and valleys. Facing the Kansas City Royals, Judge teed off for home runs No. 49 and 50 on the year, breaking Mark McGwire’s 3-decade-old MLB record for the most homers by a rookie. The record is symbolic — a nice, round number to cap off a historically great campaign — but also functional, since few players have hit half as many home runs as rookies and not gone on to turn in pretty good careers. As far as anyone can tell, Judge’s future still looks very bright, weird as this season was.

Back when we wrote about Judge’s rookie performance at midseason, he’d easily compiled the best first half to a first season of any player in recent memory. Of course, that was before the month-and-a-half stretch immediately following the All-Star Game, during which Judge hit .179, struck out in 37 consecutive games and generally saw his once-amazing numbers reduced to mere indicators of just how strange things can get in today’s era of Three True Outcomes baseball. (Despite the ridiculously low average, Judge still walked enough for a decent OBP, making it difficult to say quite how poorly he was playing.)

But by the time of Monday’s record-breaking outburst, Judge had long since dug himself out of that slump. In September, he has a 1.338 OPS — better than any of his early-season months, even — and has poured it on especially in the last two weeks and change, with four multi-homer games since Sept. 10. According to ESPN’s Stats & Information Group, Judge’s turnaround has coincided with a significant reduction in chased pitches (18 percent since Sept. 3 versus 28 percent between the All-Star break and Sept. 2) and a big hike in hard-hit balls (27 percent of at-bats versus 16 percent).

The result has been to recover one of the greatest rookie seasons by a position player in major-league history. According to Wins Above Replacement, Judge’s recent heroics have helped him edge out Mike Piazza’s 1993 and Fred Lynn’s 1975 campaigns for fifth place on the all-time list of rookie performances. Although he probably won’t catch Dick Allen’s stunning debut from 1964, which ranks fourth, Judge has still cemented his place among the top rookies ever. (As always, Mike Trout is No. 1, because of course he is.)

Judge’s place in the rookie pantheon The best rookie seasons since 1901, according to wins above replacement PLAYER YEAR AGE TEAM OPS HR WAR Mike Trout 2012 20 LAA 0.963 30 10.53 Joe Jackson 1911 23 CLE 1.058 7 9.23 Benny Kauff 1914 24 IND 0.981 8 8.82 Dick Allen 1964 22 PHI 0.939 29 8.50 Aaron Judge 2017 25 NYY 1.038 50 7.61 Fred Lynn 1975 23 BOS 0.967 21 7.25 Mike Piazza 1993 24 LAD 0.931 35 7.21 Carlton Fisk 1972 24 BOS 0.908 22 6.95 Ted Williams 1939 20 BOS 1.045 31 6.91 Albert Pujols 2001 21 STL 1.013 37 6.89 Ichiro Suzuki 2001 27 SEA 0.838 8 6.85 Corey Seager 2016 22 LAD 0.877 26 6.77 Tony Oliva 1964 25 MIN 0.916 32 6.50 N. Garciaparra 1997 23 BOS 0.876 30 6.50 Donie Bush 1909 21 DET 0.694 0 6.43 Tommie Agee 1966 23 CHW 0.773 22 6.40 Al Rosen 1950 26 CLE 0.948 37 6.39 Billy Grabarkewitz 1970 24 LAD 0.853 17 6.30 Kris Bryant 2015 23 CHC 0.857 26 6.21 Kenny Lofton 1992 25 CLE 0.727 5 6.20 WAR is an average of Baseball-Reference.com’s and FanGraphs’ versions. Rookie status is determined using current eligibility rules. Sources: Baseball-Reference.com, FanGraphs

But forget the fancy stats. Just taken by themselves, 50 homers for a rookie is absurd; even 30 is relatively unheard of, having been done just 28 times in MLB history (including twice this season — more on that later). And the rookie 30-plus homer club makes for pretty good company. Among members who’ve had at least 10 years to bash more homers after their rookie seasons, the average career total is 286 home runs, ranging from Albert Pujols’s 614 on the high side to Jimmie Hall’s 121 on the low. Most didn’t approach Pujols territory, but they did tend to settle in around 200 to 300 career homers:

Some names on the list, such as Ron Kittle, Matt Nokes and even current Red Sox left fielder Chris Young, are a little odd. If Judge follows their trajectories, he’ll finish with a career on the journeyman side, far from the halls of Cooperstown. But many more in this cohort ended up being very good ballplayers, including a handful of Hall of Fame-caliber legends — such as Pujols, Ted Williams, Frank Robinson, Piazza and our good friend Mike Trout — sprinkled in. Plus there’s Cody Bellinger of the Dodgers, the likely National League rookie of the year, who also joined the club this season with 39 homers as a rookie, his final story as unwritten as Judge’s.

Judge is such a fascinating player partly because of all the highs and lows: How can one hitter be capable of so wide a range of performance? Despite his struggles after the All-Star break, though, Judge’s entire 2017 season was historic. Nobody knows exactly what’s next for the towering slugger — particularly with the ahead-of-schedule Yankees bound for the playoffs — but we’ve already seen enough to know Judge is worth geeking out over for seasons to come.