There are things we thought we knew and things we could not have known. Raise your hand if you penciled Aaron Judge in for 50 home runs. To some, he's the new face of the Yankees.
To others, Judge represents something going on inside baseball -- more and more young players not just getting to the big leagues, but having an impact.
The Yankees are back in the playoffs because of an infusion of young talent. On the other hand, almost every playoff contender has gotten huge contributions from Major League Baseball's thriving 25-and-under generation.
Let's check out how the postseason picture has been shaped by them:

1. Yankees
This is what can happen when you have great baseball people stockpiling young talent. You can get better -- and more exciting -- faster than you probably ever imagined.
Judge could win both the American League MVP Award and the AL Rookie of the Year Award, a remarkable turnaround for a guy who hit .179 last season. He's 25. Meanwhile, the Yankees' No. 1 starter, Luis Severino, is 23. Catcher Gary Sanchez, 24, has 33 home runs. There's more talent on the way, too. Lots of it. This postseason run appears to be just the beginning of the next generation of Yankees.
2. Cubs
Are they still kids? Even after winning a World Series? Yes, most of them are. Kristopher Bryant, Willson Contreras, Addison Russell, Kyle Schwarber, Javier Baez and Albert Almora Jr. are all still in the 25-and-under club. Pretty nice foundation to build on for the next few years.

3. Red Sox
No team has gotten more from its kids than this one. Outfielder Mookie Betts is 24 and on every short list as voters consider their AL MVP Award votes. Outfielder Andrew Benintendi, 22, has 47 extra-base hits and 89 RBIs. Finally, 20-year-old Rafael Devers has an .871 OPS in 52 games since his July 25 debut at third base.
None of Boston's kids has been more important than 24-year-old lefty Eduardo Rodriguez, who has rescued the rotation with 23 starts and a 3.91 ERA. It'll be interesting to see where manager John Farrell lines him up in his postseason rotation.
4. Astros
Two of Houston's six All-Stars, shortstop Carlos Correa and right-hander Lance McCullers, are 22 and 23, respectively. Third baseman Alex Bregman, 23, has 37 doubles and 17 home runs. Right-hander Joe Musgrove, 24, has been one of baseball's best relievers down the stretch, with a 1.48 ERA in 22 games since joining the bullpen.
5. Indians
You didn't think we were going to overlook the 29-2 Indians, did you? Last season, third baseman Jose Ramirez was the guy who, in manager Terry Francona's words, "kind of saved us."
Ramirez has been even better this season. Having turned 25 last week, he is going to be one of the top three finishers in the AL MVP Award voting thanks to a season in which he has 51 -- count 'em -- doubles, six triples and 29 home runs.

6. Dodgers
Cody Bellinger, 22, made his Major League debut in the Dodgers' 21st game of the season and hit his first home run in the 25th. That began a stretch in which he homered 24 times in 53 games and the Dodgers never lost. OK, that's a stretch. They won 81 of 105.
Bellinger was so good that it has been easy to overlook the day-to-day excellence of shortstop Corey Seager, who at 23 is already arguably one of the 10 best players in the game.
7. Twins
Who says you can't slug your way into the postseason? The Twins are on the verge of doing just that. They lead the Majors in runs since the July 31 non-waiver Trade Deadline and are doing it with a string of young players who have come of age right before our eyes.
Eddie Rosario, Byron Buxton, Jorge Polanco and Eduardo Escobar have powered an improbable Minnesota push to the threshold of a first playoff appearance in seven years.
8. D-backs
Three young pitchers -- Robbie Ray, Archie Bradley and Taijuan Walker -- have helped shape one of the National League's best pitching staffs in 2017 and led the way as the D-backs return to the postseason for the first time since '11.
Ray, 25, is 14-5 with a 2.95 ERA and has emerged as a solid No. 2 starter behind Zack Greinke. Walker, 24, has a 3.54 ERA in 25 starts. Finally, there's Bradley, 24, who has been a dominant bullpen weapon with 61 appearances and a 1.41 ERA.
One year removed from the worst ERA in the Majors (5.09), Arizona's 3.69 ERA is the second best in the NL, and this is what makes the D-backs so dangerous in the postseason.

9. Rockies
The Rockies have handed the ball to 25-and-under starting pitchers in 110 of their 157 games, and they are close to returning to the playoffs for the first time since 2009.
Best of all, these young guys aren't intimidated by Coors Field. Hats off to new Rockies manager Bud Black for helping instill that mentality. Best of all, these young guys have given the Rox a solid foundation on which to build going forward.
10. Brewers
Shortstop Orlando Arcia, 23, has stabilized Milwaukee's defense and also been a solid contributor on offense for one of baseball's surprise teams. Right-hander Zach Davies, 24, has allowed two earned runs or fewer in seven of eight starts down the stretch.
11. Nationals
Shortstop Trea Turner, 24, is a dynamic presence at the top of the order. And then there's Bryce Harper, who is still only 24. His recovery from an Aug, 12 left knee injury is the No. 1 thing on manager Dusty Baker's to-do list in the final six days of the regular season.