When looking at MLB rosters, the phrase “boys of summer” may never have been more appropriate than it is now. Take the Houston Astros, for example. While Jose Altuve may be the reigning American League MVP, the defending World Series champions also boast numerous young, budding superstar-caliber players.

And then there’s the New York Yankees, who not only feature a couple of highly talented Baby Bombers (and one emerging ace), but also have younger reinforcements waiting in the wings, including a few that made a strong case to be a part of the Opening Day roster with their impressive performances in spring training.

Just how deep is MLB’s younger talent pool? Consider that for this exercise, we only focused on players who are 25 years old or younger as of Opening Day (March 29). This cut-off meant All-Stars like Mike Trout, Kris Bryant and Nolan Arenado (among others), who are the ripe age of 26, didn’t even qualify.