Edward Sutelan analyzes his top 30 MLB prospects rankings for Week 20. These MLB rookies & call-ups should make fantasy impacts in 2015, and are fantasy baseball sleepers.

UPDATE: I had mistakenly reported that Nomar Mazara had been called up to the big leagues. He in fact has been promoted to AAA, but won't be joining the big-league club at this time. If and when he does get the call in September, Mazara may be given quite a lot of playing time, especially for a team like the Rangers who could view themselves as being in playoff contention. At that time, I'd encourage fantasy owners to take a flier on Nomar Mazara, as he could contribute great fantasy production from the outfield and could be a potential four-category contributor (he won’t steal too many bases).

To be clear, this list is not the top 30 prospects in baseball. This is a list of the top 30 prospects who are likely to provide fantasy baseball value this season. The qualifications are simple: a player must not be on an active roster, they must have a clear path to the majors, and while they may have played in seasons prior to 2015, they must still have rookie eligibility. If a player is moved to the active roster of their team, they will be removed from this list and replaced.

Editor’s Note: to read about even more MLB prospects, rookies and potential call-ups, be sure to check out our MLB prospects homepage which has lots of great weekly updates and analysis.

Removed from the list
• Tyler Duffey (SP, MIN)
• John Lamb (SP, CIN)
• Chi Chi Gonzalez (SP, TEX)

Major League Prospects – Fantasy Power Rankings

1. Hector Olivera (2B/3B, ATL, AAA) – LW: 1
Stats: 83 PA, .312/.361/.442, 2 HR, 12.0% K rate, 7.2% BB rate
ETA: This Week
Once Hector Olivera is finished rehabbing his injury, he will be called up by the Braves and placed in the middle of their lineup. Expect him to be a major fantasy contributor and is a must own in the playoff stretch of fantasy baseball.

2. Jose Berrios (SP, MIN, AAA) – LW: 8
Stats: 141.1 IP, 3.18 ERA, 3.24 FIP, 9.11 K/9, 2.29 BB/9, 0.70 HR/9, 1.11 WHIP
ETA: Late August
Tyler Duffey was expectedly given the chance to start in the rotation before Jose Berrios and is likely to stay there for the rest of the season. Berrios does appear though to be not far behind him and has pitched spectacularly in his most recent starts. Fantasy owners in need of starting pitching ought to look at stashing Berrios now as he is almost guaranteed to be given a spot in the rotation.

3. Corey Seager (SS, LAD, AAA) – LW: 7
Stats: 464 PA, .295/.347/.479, 14 HR, 3 SB, 12.9% K rate, 6.9% BB rate
ETA: September Call Up
I will admit that I was wrong. I had too much faith in the Dodgers desire to win. I thought they would call up Corey Seager before rosters expand, but that never came to fruition. But he will be called up in September and should prove to the Dodgers that he is valuable in their lineup and can contribute more than Jimmy Rollins. If he impresses enough, it would not surprise me if the was their starting shortstop for Game 1 of the NLDS.

4. Byron Buxton (OF, MIN, AAA) – LW: 6
Stats: 318 PA, .303/.365/.496, 7 HR, 22 SB, 19.2% K rate, 9.1% BB rate
ETA: September Call Up
Byron Buxton was not impressive in his brief time in the majors as he really struggled to get his batting average up. Since returning from the DL, he has hit .404/.440/.532 with a home run and two stolen bases in his 11 games at Triple-A. Buxton will be called up in September and will certainly be given a chance to show that his performance earlier this year in the majors was a fluke.

5. Blake Snell (SP, TB, AAA) – LW: 16
Stats: 114 IP, 1.26 ERA, 2.73 FIP, 11.13 K/9, 3.63 BB/9, 0.47 HR/9, 1.00 WHIP
ETA: September Call Up
Blake Snell is probably going to be in the starting rotation for the Rays next season, but he will likely see his first taste of starting action in September. He has not thrown very many innings this season and could be given a chance to continue his phenomenal year in the majors. He should be considered an elite fantasy option if he gets called up for his strikeout ability and great command.

6. Zach Davies (SP, MIL, AAA) – LW: 4
Stats: 111.1 IP, 3.07 ERA, 3.22 FIP, 7.36 K/9, 3.15 BB/9, 0.40 HR/9, 1.29 WHIP
ETA: September Call Up
The Brewers are far from contention this season and they have a very young rotation that they may want to give some rest in September. Zach Davies could make himself that guy if he continues to impress in Triple-A which he has done all season for both the Orioles and the Brewers. Davies is not going to be a future ace, but he could contribute to fantasy teams this season if given the call up.

7. Robert Stephenson (SP, CIN, AAA) – LW: 2
Stats: 120.1 IP, 3.59 ERA, 3.91 FIP, 9.80 K/9, 4.79 BB/9, 0.75 HR/9, 1.24 WHIP
ETA: September Call Up
Robert Stephenson was recently removed from his Triple-A start early. It awaits to be seen whether or not he will make his next start or if they will skip him in the rotation. He would be an elite pitching option if called up and added to the Reds rotation, but his health should be carefully monitored by fantasy owners.

8. Joey Gallo (3B, TEX, AAA) – LW: 12
Stats: 325 PA, .251/.354/.556, 22 HR, 2 SB, 36.0% K rate, 13.8% BB rate
ETA: September Call Up
The Rangers recently called up Nomar Mazara to take his place in the outfield and I imagine that he will have a much more successful first taste of Major League action than Joey Gallo did. Even now in Triple-A, Gallo has continued to frustrate Rangers fans as he flashes his jaw-dropping power as well as the massive hole in his bat. He could be an elite power contributor for fantasy teams in September at the expense of a very low batting average.

9. Tyler Glasnow (SP, PIT, AAA) – LW: 3
Stats: 89.1 IP, 2.22 ERA, 2.19 FIP, 11.38 K/9, 3.43 BB/9, 0.20 HR/9, 1.11 WHIP
ETA: September Call Up
It is beginning to look more and more like the Pirates are going to wait on calling up their most prized pitching prospect until 2016, but there is still a chance that he is given a call up to the majors. With his stuff, he should not be forgotten by fantasy owners as a possible starting pitching option in September. But the risk of him not receiving the call outweighs the reward of stashing him.

10. Vince Velazquez (SP, HOU, AA) – LW: 14
Stats: 33.0 IP, 1.91 ERA, 2.63 FIP, 12.27 K/9, 3.35 BB/9, 0.55 HR/9, 1.00 WHIP
ETA: September Call Up
The Astros called up Vince Velazquez earlier this season and he absolutely dazzled with them to the tune of a 3.67 ERA and 3.06 FIP in 41.2 IP. Velazquez would certainly be an improvement over some of the Astros rotation and he could see some time making a few spot starts. Even if he is sent to the bullpen, he could be a major contributor of shut down baseball for fantasy owners.

11. Peter O’Brien (C, ARI, AAA) – LW: 11
Stats: 453 PA, .282/.330/.525, 20 HR, 1 SB, 23.2% K rate, 5.5% BB rate
ETA: September Call Up
Offensive contribution while qualifying as a catcher is the name of the game with Peter O’Brien. Playing time will be an issue for him as he will have to do battle against a great outfield for time in the field. But even with limited playing time, O’Brien could be an offensive force for fantasy owners in two-catcher leagues as a second catcher.

12. Sean Manaea (SP, OAK, AA) – LW: 10
Stats: 56.1 IP, 3.04 ERA, 3.37 FIP, 10.54 K/9, 3.04 BB/9, 0.80 HR/9, 1.31 WHIP
ETA: September Call Up
The Athletics acquired a potential front of the rotation arm for the future in Sean Manaea by dealing away Ben Zobrist to the Kansas City Royals. Because he has not pitched any where near a full season of baseball this year, he could be a candidate to take some starts for a clearly rebuilding Athletics team. He has the same issue as Tyler Glasnow where his not worth a stash because of the risk that he won’t get called up, but he would be a great help to fantasy teams if he does get the call up.

13. Josh Bell (1B, PIT, AAA) – LW: 18
Stats: 488 PA, .307/.377/.433, 6 HR, 7 SB, 11.9% K rate, 10.5% BB rate
ETA: September Call Up
The Pirates have received some of the worst offensive production from the first base position in all of baseball and they could use the extra thump from Josh Bell in their lineup. Most fantasy teams have great options at first base already, but Bell could provide some thump for fantasy owners in the position of utility or CI.

14. Aaron Altherr (OF, PHI, AAA) – LW: 15
Stats: 489 PA, .293/.367/.487, 14 HR, 16 SB, 17.2% K rate, 10.0% BB rate
ETA: September Call Up
The Phillies are typically reluctant on calling up their top prospects, but Aaron Altherr has clearly shown that he needs no more time in the minors. He would be a potential five category contributor depending on where he gets placed in the everyday lineup. If he is called up, he will not need to compete with any Phillies player for playing time.

15. Jose Peraza (SS, LAD, AAA) – LW: NR
Stats: 477 PA, .300/.324/.394, 4 HR, 28 SB, 8.0% K rate, 3.6% BB rate
ETA: September Call Up
Jose Peraza had a very brief taste of major league action when Howie Kendrick went out until Justin Turner was brought off the DL. Peraza will not likely see much time starting, but his game changing speed could be used in a similar capacity that Billy Hamilton was used for the Reds in 2013 (a pinch runner for stolen bases). Peraza is a guarantee to provide a lot of stolen bases even if given limited playing time.

16. Trea Turner (SS, WAS, AAA) – LW: 23
Stats: 485 PA, .319/.369/.456, 8 HR, 26 SB, 19.6% K rate, 7.8% BB rate
ETA: September Call Up
The Nationals are really struggling and they need a spark. I believe that in September, Trea Turner will be that spark. Ian Desmond has had arguably the worst season of his career while Trea Turner has really made a name for himself in the minors. With Turner’s offensive ability, he could provide a major spark for the Nationals at the top of that lineup and could provide great fantasy production at the shortstop position. There is no guarantee that he will receive a lot of playing time, but he would provide great production for fantasy owners.

17. Aaron Blair (SP, ARI, AAA) – LW: 17
Stats: 131.1 IP, 2.95 ERA, 3.99 FIP, 7.40 K/9, 2.81 BB/9, 0.82 HR/9, 1.18 WHIP
ETA: September Call Up
Aaron Blair could be used as a starting option for the Diamondbacks in September as many of their starters are going to be on strict innings limit. Patrick Corbin will be limited on his playing time and Blair could be seen as the top option to replace him in the rotation in the middle of September. Until then, Blair will likely see time in the bullpen and could be a great relief option for fantasy owners in desperate need of starting pitching.

18. CJ Edwards (RP, CHC, AAA) – LW: 19
Stats: 53.1 IP, 2.70 ERA, 3.28 FIP, 12.32 K/9, 6.75 BB/9, 0.17 HR/9, 1.22 WHIP
ETA: September Call Up
CJ Edwards, now a relief pitcher, will have his fantasy value very limited, but that doesn’t mean he can’t be a Wade Davis or Dellin Betances type fantasy relief option for fantasy owners. He may not see many or any save opportunities with his command issues that he has demonstrated this year, but he has elite strikeout stuff that could help fantasy owners in need of pitching help.

19. Alex Meyer (SP/RP, MIN, AAA) – LW: NR
Stats: 80.2 IP, 5.47 ERA, 3.48 FIP, 9.48 K/9, 4.91 BB/9, 0.45 HR/9, 1.70 WHIP
ETA: September Call Up
Alex Meyer has been much better than his ERA would have you believe. Sure, Meyer was really kicked around in the majors, but he has shown in the minors that he has the potential to be a great relief pitcher. Because the Twins still view him long term as a starter, he could receive a spot start or two if it looks like they will fall out of Wild Card contention. Meyer is a risk that should only be taken by fantasy owners in a dire need of pitching.

20. Aaron Judge (OF, NYY, AAA) – LW: 22
Stats: 458 PA, .269/.341/.474, 18 HR, 6 SB, 26.4% K rate, 9.6% BB rate
ETA: September Call Up
The Yankees are going to be in a hotly contested race with the Blue Jays for the AL East crown and they could use any help they can get. Their outfield is very left-handed heavy and Aaron Judge could be used as an occasional platoon starter for the Yankees. If he is used in this capacity, fantasy owners are encouraged to take the risk on Judge’s playing time just because of the great offensive contribution he could provide.

21. Trevor Story (SS, COL, AAA) – LW: NR
Stats: 479 PA, .277/.347/.519, 18 HR, 18 SB, 24.8% K rate, 8.8% BB rate
ETA: September Call Up

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22. Gary Sanchez (C, NYY, AAA) – LW: NR
Stats: 367 PA, .274/.335/.482, 16 HR, 7 SB, 19.1% K rate, 7.9% BB rate
ETA: September Call Up

23. Tyrell Jenkins (SP, ATL, AAA) – LW: 21
Stats: 136.2 IP, 3.23 ERA, 4.02 FIP, 5.80 K/9, 3.95 BB/9, 0.46 HR/9, 1.36 WHIP
ETA: September Call Up

24. Brett Phillips (OF, MIL, AA) – LW: 25
Stats: 536 PA, .314/.382/.540, 16 HR, 17 SB, 20.7% K rate, 8.0% BB rate
ETA: September Call Up

25. Mike Wright (SP, BAL, AAA) – LW: 28
Stats: 71.0 IP, 2.41 ERA, 3.06 FIP, 7.48 K/9, 2.79 BB/9, 0.38 HR/9, 1.08 WHIP
ETA: September Call Up

26. Adam Duvall (1B, CIN, AAA) – LW: 24
Stats: 495 PA, .269/.313/.534, 30 HR, 4 SB, 20.6% K rate, 5.3% BB rate
ETA: September Call Up

27. Michael Fulmer (SP, DET, AA) – LW: 26
Stats: 109.2 IP, 1.97 ERA, 2.63 FIP, 8.78 K/9, 2.22 BB/9, 0.41 HR/9, 1.07 WHIP
ETA: September Call Up

28. Jake Thompson (SP, PHI, AA) – LW: 27
Stats: 107.2 IP, 4.18 ERA, 4.01 FIP, 7.27 K/9, 3.18 BB/9, 0.75 HR/9, 1.33 WHIP
ETA: September Call Up

29. Christian Walker (1B, BAL, AAA) – LW: 30
Stats: 496 PA, .258/.321/.416, 14 HR, 1 SB, 22.6% K rate, 7.9% BB rate
ETA: September Call Up

30. Alen Hanson (2B, PIT, AAA) – LW: 29
Stats: 454 PA, .269/.317/.401, 6 HR, 30 SB, 17.4% K rate, 6.8% BB rate
ETA: September Call Up

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