13. Reyes Moronta
This stocky Dominican right-hander got a look in the Northwest League as a 20-year-old in 2013 and struggled. He was demoted back to the Arizona League for 2014, and since, has struck out 188 batters in 128 innings. He had a breakout year in 2016 in the California League, especially from May 4 on, where he allowed just under one hit per two innings and gave up only nine extra-base hits over a 50-game stretch. He's been a lethal late-inning threat with his explosive mid-to-upper 90s (and now even 100s) fastball and mid-80s slider, but will get tested in the upper minors as more experienced hitters face what has been at times a below-average command pitcher.
14. Jordan Johnson
Jordan Johnson went from 23rd-rounder to Top-20 prospect with one breakout half-season. Johnson, a native of Elk Grove, Calif. who went to Franklin High School and Cal State Northridge, began the 2015 season late in rookie ball while building strength back up from a minor tear in his lat muscle. He joined the San Jose Giants, jumping over Class-A Augusta, in early August where he made six starts and was crucial for the team in the rotation during their playoff run. Johnson ended the regular season with a 4.2 inning, 10-strikeout performance that opened many eyes. Johnson features a low-to-mid 90s four-seam fastball with moderate running action, a 12-6 curveball, a circle-changeup, and is currently in the process of adding a two-seam fastball.
15. Sandro Fabian
At 19 years-old, Sandro Fabian is arguably the most exciting young prospect in the system. Despite a trip to the AZL in 2016, followed by four days at Spring Training in March, I was unable to get any noteworthy footage of the Dominican outfielder, who signed with San Francisco in July of 2014 for half a million. Fabian used his strong hands and what Fangraphs' Eric Longenhagen calls "natural bat-to-ball ability" to rake the Arizona League in his United States debut, slugging .522 with a .182 ISO in 174 plate appearances. Many see Fabian as a corner outfielder, and in 2017 with the Augusta GreenJackets, he'll likely see most of his reps in right field while Ashford Fulmer mans center field.
16. Dan Slania
A late-inning reliever for most of his baseball life, Dan Slania moved into a starting pitcher role mid-2016, and has made the Giants look like geniuses with his numbers thus far. In his first 11 starts since the role switch, Slania has thrown more than 80 pitches eight times, and thrown more than 90 pitches six times, while averaging six innings per start and just 6.7 hits per nine innings. Slania uses a low-to-mid-90s sinking fastball, as well as a cutter and a slider. The cutter can touch 91-92 but typically is a high-80s pitch, while the slider sits 81-85. Almost all of his already-solid numbers have improved since becoming a starter. What a story Slania could be over the next couple years.