Vladimir Guerrero Jr. or Fernando Tatis Jr.?

That was the question when we tried to determine who should stand atop MLB Pipeline's preseason Top 100 Prospects list. That's the question again as we partake in our annual exercise of ranking this year's graduated prospects based on their future value.

Some scouts believe Guerrero's offensive upside ranks with any prospect's in recent memory, while Tatis offers 30-30 potential that's rarely found in a shortstop. While neither will win a Rookie of the Year award, they've shown why they were held in such high regard.

We’re only considering players who will lose their rookie eligibility by season's end, so that's why you won't find Gavin Lux, Kyle Tucker, Dustin May or Sean Murphy on our list below. Production in the current season matters, as does previous track record, and age is an important factor (which is why we've included everyone's seasonal age as of July 1 in parentheses). Success at a young age bodes well for future stardom, so with apologies to 26-year-old John Means and 28-year-old Mike Yastrzemski, here's our Top 30:

1. Vladimir Guerrero Jr., 3B, Blue Jays (20)
The second coming of Miguel Cabrera is hitting .269/.340/.441 -- Cabrera batted .268/.325/.468 at the same age -- and has posted a .291/.355/.472 line since the All-Star break.

2. Fernando Tatis Jr., SS, Padres (20)
An argument can be made for Tatis' all-around ability over Guerrero's offensive capability, and he has posted more WAR per 162 games (8.1) than any rookie this year while battling injuries.

3. Yordan Alvarez, OF, Astros (22)
Since 1900, only four players who were as young as Alvarez and logged as many plate appearances topped his 178 OPS+: Ted Williams, Bryce Harper, Ty Cobb and Mike Trout.

4. Eloy Jimenez, OF, White Sox (22)
He has had an up-and-down year and his defense has been atrocious, but he's finishing strong and on pace to become just the 11th rookie ever to slug 30 homers at age 22 or younger.

5. Bo Bichette, SS, Blue Jays (21)
Bichette's .315/.355/.592 line in 197 plate appearances has been topped by just two shortstops his age or younger in baseball history: Alex Rodriguez and Tatis.

6. Keston Hiura, 2B, Brewers (22)
And now for second basemen . . . Hiura's .302/.370./571 performance in 297 plate appearances produces the highest OPS (.941) for his age or younger, just ahead of Pete Browning's .940 in 1882.

7. Victor Robles, OF, Nationals (22)
He already is one of the fastest runners and best defenders in the game, and while his exit velocities rank near the bottom, he still has 52 extra-base hits.

8. Pete Alonso, 1B, Mets (24)
His 47 homers already have set records for the Mets and for National League rookies, and put him within five of Aaron Judge's all-time rookie mark.

9. Mike Soroka, RHP, Braves (21)
He ranks second in the Majors with a 2.57 ERA and first with a 1.80 ERA+ -- the third-best since 1900 for a pitcher age 21 or younger, trailing only Dwight Gooden and Vida Blue.

10. Alex Verdugo, OF, Dodgers (23)
The Dodgers finally found room for him in their outfield, and he has responded by hitting for average and power while providing better-than-expected defense.

11. Nick Senzel, OF, Reds (24)
He's better suited for second or third base than center field and must prove he can stay healthy, though he still has solid or better tools across the board.

12. Chris Paddack, RHP, Padres (23)
He had the best changeup and command in the Minors last year, and they translated into immediate big league success as well as a 4.8 K/BB ratio in 135 2/3 innings -- trailing only Masahiro Tanaka, Roy Oswalt, Noah Syndergaard and Matt Shoemaker among rookies who have worked that much since 1900.

13. Brendan McKay, LHP/DH, Rays (23)
He developed faster as a pitcher than a hitter, which could spell the end of his quest to be a full-fledged two-way player, but he shows signs of becoming a frontline starter in the near future.

14. Will Smith, C, Dodgers (24)
An outstanding receiver with Gold Glove upside, he homered 12 times in his first 28 games to tie Rhys Hoskins' big league record after going deep just nine times in three college seasons at Louisville.

15. Luis Urias, SS/2B, Padres (22)
Though he has yet to produce in San Diego after excelling in the Minors, he still should hit for average with sneaky power and defensive versatility.

The next 15

16. Francisco Mejia, C, Padres (23)

17. Griffin Canning, RHP, Angels (23)

18. Dylan Cease, RHP, White Sox (23)

19. Mitch Keller, RHP, Pirates (23)

20. Alex Reyes, RHP, Cardinals (24)

21. Austin Riley, OF/3B, Braves (22)

22. Bryan Reynolds, OF, Pirates (24)

23. Brandon Lowe, 2B, Rays (24)

24. Michael Chavis, INF, Red Sox (23)

25. Isan Diaz, 2B, Marlins (23)

26. Cole Tucker, SS, Pirates (22)

27. Kevin Newman, SS/2B, Pirates (25)

28. Zac Gallen, RHP, Diamondbacks (23)

29. Luis Arraez, INF/OF, Twins (22)

30. Sandy Alcantara, RHP, Marlins (23)