This season was littered with top-prospect debuts because of expanded rosters and the lack of a true developmental minor league system. From my winter top 100, 39 players have already reached the major leagues, with 28 of them making their debuts this season. While it's fun to talk about what could be in the future, the MLB playoffs are looming and very few recent call-ups will be key players as we enter October. There's a mess of outstanding young talent in the game, so I'm choosing to focus on the best young players in the game.
This list is of all players age 25 or younger whose teams have made the playoffs. I'm ranking them in order of which ones I'd prefer over the next five seasons. This way, having made a real contribution and getting regular playing time this year is a key factor, and the list is made up almost entirely of players who have lost their prospect eligibility.
Because of that, this isn't just the best for long-term upside (or else the top prospect in baseball, Rays SS Wander Franco, would be on here) and it isn't simply for trade value, since we're using a uniform five years with no salary considerations, while control years and salary vary a lot player to player. I'm also leaving out players who have opted out of the season (such as White Sox RHP Michael Kopech), those who are already out for the year because of injury (Braves RHP Mike Soroka, A's LHP A.J. Puk, Astros DH Yordan Alvarez, Rays LHP Brendan McKay), and obviously those who just missed the age cutoff (Brewers RHP Devin Williams).