2015 wasn't the best year to be a prospect for the Seattle Mariners. Their pre-season Top-10 prospect list seemed like it took most of the year off, with struggles up and down, injuries and even a tragic accident. But while many of the more established, more highly ranked prospects in the organization heading into 2015 endured a season of disappointment, several new faces in the system put up very strong debuts. Here is our list of the nine players who enjoyed the best stateside system debuts for Seattle in 2015, from lowest level played to highest.
Nick Neidert, right-handed pitcher, AZL (Peoria) Mariners, 2015 Draft, 2nd round (Peachtree HS (GA))
Neidert didn't exactly blow away the AZL, compiling huge strikeout totals the way that many young, highly drafted high school pitchers do. But the M's top pick pitched quite well in his debut, posting the best ERA (1.53) and fourth lowest H/9 (6.4) of any pitcher who made at least seven starts there. Neidert walked only nine batters in his 11 games and had a nice 2.55 GO:AO ratio while allowing just five extra base hits out of the 135 batters he faced. Neidert, who won't turn 19 for more than two months still, also held right-handed hitters to a combined .432 OPS in their 83 plate appearances and helped his catchers gun down more than half of the base runners that attempted to steal against him. Although he is just 6-foot, doesn't stay tall (by design) in his delivery and has a low three-quarters arm slot, Neidert has good velocity. He should find himself out of the Rookie level next year, ready to take on a bigger challenge and a bigger workload.
Matt Walker, right-handed pitcher, AZL (Peoria) Mariners, 2015 Draft, 36th Draft (Weatherford JC)
Walker, a late pick out of junior college by the Mariners this season, only threw 21 1/3 innings in 14 appearances, but he definitely impressed in that limited showing. The 6-foot-6 right-handed posted the fifth best SO/9 mark (13.1) in the league, fanning 31 of the 85 batters he faced in that abbreviated debut, including more than half (26 of 51) of the right-handed hitters. Walker doesn't have hugely overpowering stuff, working 90-92 with his fastball and also possessing a slider and changeup, but he pounds the zone low and has good movement on his fastball, generating a lot of ground balls.
Drew Jackson, shortstop, Everett AquaSox, 2015 Draft, 5th round (Stanford)
Although he tailed off towards the end of the regular season, Jackson was legitimately flirting with the 39 year old Northwest League record for batting average (.403 in 1976) late into the year thanks to going on an impressive tear that took his already very good season to the next level. He had a 20-game hitting streak from July 19th to August 15th in which he averaged more than two hits per game and hit .513 (41-for-80), scoring 31 runs, driving in 14 and stealing 20 bases. He finished his debut season leading the NWL in AVG (.358), OBP (.432), SB (47) and runs scored (64) while ranking 2nd in hits (81) and 4th in SLG (.447). That stolen base total was almost 50% more than the next closest competitor. Combined with his plus defensive play at shortstop, I expect Jackson -- who was an All-Star and was twice named the Player of the Week this season in the NWL -- to have a lot of support for the MVP.
Andrew Moore, right-handed pitcher, Everett Aquasox, 2015 Draft, 2nd round (Oregon State)
Moore, like Neidert, earns the stigma from scouts for being a "short" right-handed starter, but the 6-footer showed in his pro debut that he was more than just a "pitchability" guy. Moore walked just two (both left-handed hitters) in his 39 innings and consistently showed the ability to get ahead and get hitters out dispite his somewhat predictable work in the zone. He struck out 43 while following a very similar plan that Ryan Yarbrough did a year ago in terms of workload, never pitching more than three innings in any outing. His fastball has been in the mid-90s in the past, although in Everett he worked more in the low-90s with a curve and change to compliment that pitch. But location and smarts make him the pitcher he is. He'll jump up to full-season ball next year and should find success with his approach.
Joe Pistorese, left-handed pitcher, Everett Aquasox, 2015 Draft, 17th round (Washington State)
A season that was bursting with positives ended with a huge negative for Joe when the former Cougar was suspended 50-games for testing positive for amphetamines in violation of the drug program. Before the suspension came down, the Bellevue native had dominated in his 16 relief appearances for the AquaSox, holding opposing hitters to a .182 AVG while putting up a 1.28 ERA and 0.83 WHIP with a strikeout-to-walk ratio of better than 6.5-to-1. Pistorese's best offering is his curve, and he also has a lot of deception in his delivery, hiding the ball well. With the plus curve and a fastball in the 90-92 range leading his offerings, Pistorese figures to get a chance to slate in a rotation next year once he's eligible to return.
Braden Bishop, outfielder, Everett Aquasox, 2015 Draft, 3rd round (Washington)
Bishop, who made a name for himself while at U-Dub as a standout defender with a handful of highlight reel catches in the outfield, adjusted to the pro game with the bat better than expected in Everett, finishing the season as the Northwest League's number two hitter in terms of average at .320, behind only teammate Drew Jackson. And while his plate discipline numbers weren't the best (only five walks with 33 strikeouts in his 248 plate appearances), that didn't stop him from being a consistent threat in the box. Bishop is still very slightly built, but he found the gaps frequently enough to tally up the 12th best OPS in the league (.760). He was also plunked a league-high 12 times and was a force once he got on base as he stole 13 bases in 16 attempts and scored 34 runs in the 56 games he played. Seattle has tabbed a few defense-first center fielders in the draft the past few seasons, but Bishop's debut is the most encouraging out of that group.
Anthony Misiewicz, left-handed pitcher, Everett Aquasox, 2015 Draft, 18th round (Michigan State)
Misiewicz got into 14 games for Everett this year, half as a starter and half out of the pen -- working in tandem with Andrew Moore. Regardless of the role, the 6-foot-1 Spartan lefty was very, very good. Opponents hit just .189/.234/.270 off of him on the season as he got as many strikeouts (40) as he allowed baserunners (30 hits, 10 walks) in his 46 1/3 innings. His 2.14 ERA was the best in the Northwest League among pitchers with at least as many innings as Anthony threw, and his 5.8 H/9 mark was seventh best in the league, as was his 0.86 WHIP. The sinking action on his low-90s fastball and his ability to get in on hitters led to a lot of ground balls, and his standard four-pitch mix should give him a shot as a full-time starter in 2016.
Mike Montgomery, left-handed pitcher, Seattle Mariners, Trade (CHC 1st round, 2008, William S. Hart HS (CA))
Montgomery came to Seattle in exchange for Erasmo Ramirez at the end of spring training as a former top prospect, but having not yet reached Triple-A in his time with Kansas City of Tampa Bay, he certainly wasn't looked at as someone who would contribute like he has at the big league level here in 2015. The lefty did just that, though, as he threw back-to-back shutouts in his fifth and sixth career starts -- the first a dazzling 10 strikeout performance against those Royals -- and he is still tied for the American League lead in that category despite having some struggles in more recent starts and then being shut down. Despite those struggles, Montgomery gave the M's nine Quality Starts and pitched well enough to win in 12 of his 16 starts to date. He doesn't look like an ace, but he is a legitimate big league pitcher that could help the club and he is still young enough to project a bit.
Tony Zych, right-handed pitcher, Seattle Mariners, Trade (CHC 4th round, 2011, Louisville)
A pre-season trade acquisition, Zych -- who was ranked in the Cubs' Top-30 prospects two years in a row by Baseball America in the past -- seemed to finally put it together a bit in 2015 in Tacoma for the M's after enduring some struggles the past three seasons. Working with a fastball that sits in the mid-90s, Zych found enough consistency with his slider and his command that he more than tripled his SO:BB ratio from the previous three years and earned himself a promotion to Seattle once rosters expanded. The 25 year old figures to get a real shot at sticking with the big club in 2016 spring training as a middle inning guy.
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