The big baseball argument of this generation is back on.
I'm not talking about steroids, the designated hitter rule or guessing the next time Jonathan Papelbon will make a scene. I'm talking Trout versus Harper.
Back in 2011 or so, the "Who's better between Trout and Harper?" argument was quite common, and for good reason. They were two of the top prospects in baseball, both very young -- and very talented -- phenoms with bright futures. Then something happened to put that argument on the back burner: Mike Trout took a giant step forward and became the best player in baseball. Bryce Harper certainly didn't disappoint; a 122 OPS+ through his age-21 season is nothing to scoff at. But that wasn't quite up to what Trout achieved in the majors, a 28.6 career WAR (baseball-reference version) through his age-22 season. To put that 28.6 in context, that's already more than half the entire career WAR of borderline Hall of Famers such as Jim Rice or Jim Bottomley (Trout actually passed "Sunny Jim" by this year's All-Star break).
But a funny thing has happened on the way to Cooperstown: Harper's rejoined the race and rekindled the debate.
From a projection standpoint, coming into this season, there was quite a separation between Trout and Harper. Sure, the ZiPS projection system still liked Harper enough to rank him second in MLB among players under age 25, but the difference was massive, by some 40 projected WAR. By more traditional stats, ZiPS had Trout finishing with 900 more hits, 100 more home runs, 400 more RBIs ... You get the idea.
The difference, of course, was that Trout already had his huge breakout and became a perennial MVP candidate. As much as everybody liked Harper and believed he had almost unlimited upside remaining, actually taking that step makes a player a much more valuable commodity than someone who might, maybe or probably will accomplish it.
In 2015, it happened.
By baseball-reference's reckoning, his 1.120 OPS and 200-plus OPS+, combined with solid defense in right field, Harper has been worth 10.2 WAR during the 2015 season. Among position players, that currently ranks 12th in modern baseball history for a player under 25. If you look at the list of 10-WAR players under 25, in the corresponding table, you'll see a list of clear disappointments and flash-in-the-pans.
I assume you've surmised by now that I was being sarcastic: Every single position player under 25 with a 10-WAR season who is eligible for the Hall of Fame is not only in the Hall of Fame but considered an inner-circle Hall of Famer. (Sure, A-Rod could have some trouble getting to the Hall of Fame, but that's for, uh, a different reason.)
In fact, if you keep rolling down the list of top under-25 performances in search of someone eligible who's not in the Hall of Fame, you'd have to go all the way down to Dick Allen in 33rd place; he posted an 8.8 WAR in his age-22 season. Of the top 50 under-25 seasons, only a single one was by a hitter with a weak Hall of Fame case, Willie Wilson's 1980 season (defensive numbers can be volatile).
In other words, Harper's 2015 season is something that only Hall of Fame-type players are able to do. Let's look a bit forward. How has this season changed his long-term outlook? I could cheat and just say "a whole lot," but given that I'm a baseball writer with a well-known projection system, I guess we have to actually crunch the numbers.
While Trout still comes out ahead, the gap has definitely narrowed. Whereas Trout was a good 40 projected WAR in front of Harper before this season, as previously noted, he's just 22 WAR now: Trout has a 123 projected WAR (which is absolutely insane, by the way), while Harper is projected with a career WAR total of 101 wins. (Third place remains Manny Machado down at 76 WAR.) The projected home run total jumps to 596 (from 426, and even above Trout's 576), 2,700 hits, nearly 1,700 RBIs ... and a plaque in Cooperstown.
If you think you'll be tired of Harper-Trout argument, you're lying to yourself. One of the best things about awesome stuff is, well, arguing about awesome stuff. Mays versus Mantle. Ruth versus Cobb. Clemens versus Maddux. Whether a hot dog is a sandwich (um, no!). Great taste versus less filling. Pixies versus Nirvana. The battle between Harper and Trout over the next decade is likely going to be the stuff of legend, one of those great battles that history looks back on, and we get to live this one! So let's get ready to rumble. Um, not you, Paps.