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Tyler O'Neill
Tyler O'Neill
Mark J. Rebilas-USA TODAY Sports

Seattle Mariners Top 20 Prospects for 2017

The list and grades are a blending of present performance and long-term potential. Comments are welcome, but in the end all analysis and responsibility is mine. All of these grades are subject to change as the winter progresses. The final grades will be finished sometime in February when all 30 teams are complete.


Grade A prospects are the elite. In theory, they have a good chance of becoming stars or superstars. Theoretically, most Grade A prospects develop into stars or at least major league regulars, if injuries or other problems don’t intervene. Note that is a major "if" in some cases.

Grade B prospects have a good chance to enjoy successful careers. Some will develop into stars, some will not. Most end up spending several years in the majors, at the very least in a marginal role.

Grade C prospects are the most common type. These are guys who have something positive going for them, but who may have a question mark or three, or who are just too far away from the majors to get an accurate feel for. A few Grade C guys, especially at the lower levels, do develop into stars. Many end up as role players or bench guys. Some don’t make it at all.

Finally, keep in mind that all grades are shorthand. A Grade C prospect in rookie ball could end up being very impressive, while a Grade C prospect in Triple-A is likely just a future role player.

1) Kyle Lewis, OF, Grade B+: Age 21, first round pick in 2016 out of Mercer; hit .299/.385/.530 with three homers, 16 walks, 22 strikeouts in 117 at-bats in Northwest League; everything was going well until season ended early with serious knee injury; may not be ready to play again until July and injury was bad enough that it may reduce his speed enough to keep him out of center field; good plate discipline, above-average bat speed and power should carry him even at a corner; makeup is highly-regarded and that should help with recovery process. ETA late 2018.

2) Tyler O’Neill, OF, Grade B+: Age 21, third round pick in 2013 from high school in Canada; hit .293/.374/.508 with 24 homers, 62 walks, 12 steals, 150 whiffs in 492 at-bats in Double-A; 65 power, maybe even a 70, due to outstanding bat speed and strength; has improved reads on breaking balls but still strikes out a lot, threatening to impede batting average and OBP at higher levels; that said, if he can hit .250-.260 the power will be enough to play regularly and he’s shown ability to make adjustments; high school catcher has developed into an under-rated right fielder with a strong arm and more range than you’d expect; ETA late 2017.

3) Nick Neidert, RHP, Grade B-/B: Age 20, second round pick in 2015, posted 2.57 ERA with 69/13 K/BB in 91 innings in Low-A, 75 hits; 90-94 fastball and good control give a strong basis for development; has a curve, slider, and change, all with at least average potential; strikeout rate is low and reflects need to gain more consistency with the secondaries; Midwest League observers saw a future number three starter if two of the secondaries sharpen up, which seems very plausible; mound presence and makeup are also positives. ETA late 2019 or 2020.

4) Dan Vogelbach, 1B, Grade B-/B: Age 24, acquired from Cubs in July trade; hit .292/.417/.505 with 23 homers, 97 walks, 101 strikeouts in 459 at-bats in Triple-A, went 1-for-12 in the majors; despite 6-0, 250 build he is not a brute-force slugger; he has legitimate pure hitting skills with advanced strike zone judgment and a clean swing to go with his 60-grade power; limited to first base; he doesn’t make many errors but lacks range; should hit enough to be a long-term DH if he loses too much glove as he gets older. ETA 2017.

5) Max Povse, RHP, Grade B-: Age 23, acquired from Braves in November trade; huge 6-8 right-hander with fastball at 91-95, 3.36 ERA with 139/29 K/BB in 158 innings between High-A and Double-A; will mix in very good change-up and an average curveball; he could be an inning-eating horse and Seattle should be a good environment for him; originally third round pick in 2014 from UNC-Greensboro. ETA: late 2017.

6) Rob Whalen, RHP, Grade B-: Age 22, acquired from Braves in November trade; excellent in Double-A/Triple-A (2.40, 112/44 in 120 innings, 99 hits) but hit hard at times in five major league starts (6.57, 25/12 K/BB in 25 innings) but maintained strikeout pace; season ended early with shoulder fatigue; deceptive approach with good change-up and a fastball around 90, back-end starter projection. ETA: 2017.

7) Mitch Haniger, OF, Grade B-: Age 26, first round pick by Brewers back in 2012 from Cal Poly, traded to Arizona in 2014, then on to Seattle in Taijuan Walker deal; hit .321/.419/.581 with 25 homers, 69 walks, 99 strikeouts in 458 at-bats between Double-A and Triple-A, then .229/.309/.404 in 109 at-bats in the majors; an older prospect with a mixed track record, development was slow due to injuries and fouled swing mechanics but has always had good tools including at least average power, decent speed, and a strong arm; step forward in ’16 seems legit although a lot of his power production was in the friendly PCL; realistically should be able to hit .260 with good power; ETA 2017.

8) Andrew Moore, RHP, Grade B-: Age 22, compensation round pick in 2015 from Oregon State; posted 2.65 ERA with 133/31 K/BB in 163 innings between High-A and Double-A, 148 hits; fastball peaks at 93 and is usually right at 91; however it plays up due to his command; mixes in curve, slider, change-up; none of his pitches individually grade more than average but his pitching instincts are exceptional; on paper a future number four starter, but don’t under-estimate him. ETA 2018.

9) Brayan Hernandez, OF, Grade B-/C+: Age 19, switch-hitter from Venezuela signed for $1,850,000 in 2014; hit .281/.327/.433 with 21 steals, 17 walks, 59 strikeouts in 263 at-bats between Dominican Summer League and Arizona Rookie League; best tool is 60-grade speed, has some raw power too but needs to improve plate discipline; you can dream on him being a 20-steal, 15-homer guy if he can make further gains with the strike zone. ETA 2021.

10) Drew Jackson, SS, Grade C+: Age 23, fifth round pick in 2015 out of Stanford; hit .258/.332/.345 with six homers, 16 steals, 50 walks, 105 strikeouts in 524 at-bats in High-A; best-known for speed and throwing arm, can remain at shortstop with just a bit more reduction in error rate as the physical tools play there just fine; fun player to watch, as his athleticism stands out on any field; didn’t have a great offensive year in the Cal League but I think he’s capable of better and I like him better than the numbers say I should, though I expect he’ll develop more slowly than typical college bat; ETA 2019.

11) Guillermo Heredia, OF, Grade C+: Age 26, Cuban outfielder signed in March, 2016 for $507,000; did not play in 2015 but despite rust he hit .300/.395/.391 with 48 walks, 47 strikeouts in 343 at-bats between Double-A and Triple-A, and .250/.349/.315 in 92 major league at-bats; disciplined hitting approach and runs well but lacks big home run power, will rely on OBP skills which look solid right now; superior defensive outfielder capable at all three positions; should be productive fourth flycatcher. ETA 2017.

12) Dan Altavilla, RHP, Grade C+: Age 24, fifth round pick in 2014 out of Mercyhurst; posted 1.91 ERA with 65/22 K/BB in 57 innings in Double-A, then 0.73 ERA in 12 innings in the majors with 10/1 K/BB; converted starter took well to bullpen, showing mid/upper-90s fastball and hard slider; control was very sharp in the majors; should be a very effective short and middle reliever and might get a chance to close games eventually. ETA 2017.

13) Dillon Overton, LHP, Grade C+: Age 25, second round pick by Athletics in 2013 from University of Oklahoma, acquired by Mariners on January 26th for minor league catcher Jason Goldstein; posted 3.29 ERA with 105/31 K/BB in 126 innings in Triple-A, 132 hits; rung up for ugly 11.47 ERA in 24 major league innings due to allowing .407 average against; he’s better than that; fastball never came all the way back following Tommy John, is now in upper-80s but curveball and change-up are solid and he throws strikes, classic fifth starter type. ETA 2017.

14) Christopher Torres, SS, Grade C+: Age 18, signed in 2014 from Dominican Republic for $375,000; unusual case in that he reportedly had agreed to sign with Yankees for more than $2 million but deal fell through; hit .257/.337/.359 with 12 steals, 19 walks, 44 strikeouts in 167 at-bats in rookie ball; 60 speed and 60 arm, has tools to stay at shortstop if he can cut back on mistakes of youth; chance to hit for average with gap power down the line. ETA 2020 or 2021.

15) Ben Gamel, OF, Grade C+: Age 24, 10th round pick by Yankees in 2010, traded to Mariners in August; hit .308/.365/.420 with six homers, 19 steals, 43 walks, 94 strikeouts in 483 at-bats in Triple-A, .188/.278/.292 in 48 major league at-bats; line drive bat with occasional pop and above-average speed; good defensive ability due to more to feel/instinct than pure tools though arm is respectable; fourth outfielder potential, between Gamel and Heredia the Mariners should have backup outfield depth covered well. ETA 2017.

16) Shae Simmons, RHP, Grade C+: Age 26, originally drafted by Braves in 22nd round in 2012, traded to Mariners on January 11th in Mallex Smith/Luiz Gohara deal; posted 1.96 ERA in 18 innings in minors, coming off Tommy John surgery, and 1.35 in 6.2 MLB innings; has 2.54 ERA in 28 major league innings with 26/11 K/BB dating back to 2014, not technically a rookie due to service time but under the inning limit; MLB stats are not a fluke: he’s retained his heavy 95 MPH fastball and is ready to help now. ETA 2017.

17) Emilio Pagan, RHP, Grade C+: Age 25, 10th round pick in 2013 from Belmont Abbey; posted 2.49 ERA with 84/29 K/BB in 65 innings between Double-A and Triple-A with 47 hits allowed, 10 saves in 11 chances; fanned 12 in 11 innings in Arizona Fall League though eight walks helped lead to 6.55 ERA; another middle relief type with 95 MPH fastball and a hard slider, chances will depend on how well his command holds up. ETA 2017.

18) Thyago Vieira, RHP, Grade C+: Age 23, signed out of Brazil in 2010, posted 2.84 ERA with 53/18 K/BB in 44 innings in High-A, 37 hits; huge step forward after poor years in 2014 and 2015; mid-upper-90s fastball with some reports as high as 102; also has an above-average curveball; all a matter of command here, there’s no shortage of stuff and he showed signs of being a pitcher and not just a thrower in ’16; behind on Altavilla, Simmons and Pagan on the "get a chance in the bullpen" list but has very high upside. ETA 2018.

19) Joe Rizzo, 3B, Grade C+: Age 18, second round pick in 2016 from high school in Virginia; hit .291/.355/.392 with 17 walks, 36 strikeouts in 148 at-bats in rookie ball; praised for line drive bat and pure hitting ability along with excellent make-up; main problem is position, as he lacks the pure power for a classic third baseman or corner position but doesn’t run well enough to fit elsewhere; if he hits enough they will find a spot somewhere. ETA 2020.

20) Greifer Andrade, 2B, Grade C+: Age 20, signed out of Venezuela in 2013 for $1,000,000; hit .341/.396/.549 with five walks, 17 strikeouts in 82 at-bats in Arizona Rookie League; flashy line drive hitter with a bit of pop in the bat; impatient and will have to watch plate discipline at higher levels but should continue to hit for high averages; decent glove at second but lacks instincts to play shortstop regularly; ETA 2020.

OTHER GRADE C+: Braden Bishop, OF; Bryson Brigman, SS; Pablo Lopez, RHP; Brandon Miller, RHP; D.J. Peterson, 1B; Tony Zych, RHP

GRADE C: Rayder Ascanio, SS; Zac Curtis, LHP; Joe DeCarlo, 3B; Ronald Dominguez, RHP Eric Filia, OF; Paul Fry, LHP; Darin Gillies, RHP; Ryne Inman, RHP; Luis Liberato, OF Marcus Littlewood, C; Tyler Marlette, C; Ian Miller, OF; Gareth Morgan, OF; Taylor Motter, UT; James Pazos, LHP; Boog Powell, OF; Joseph Rosa, 2B; Tyler Smith, INF; Dylan Unsworth, RHP; Kyle Waldrop, OF; Donnie Walton, INF; Gianfranco Wawoe, 2B; Nick Wells, LHP Nick Zammarelli, 3B-OF; Jake Zokan, LHP

Lots of C+ in this system which could be ordered any number of ways. I will be in the comments to discuss.