Braves outfielder Ronald Acuna and D-backs right-hander Jon Duplantier had barely left an impression as pros when the 2017 season began. Acuna had played just 40 games in full-season ball, while Duplantier had worked just one inning in a pro debut truncated by elbow soreness.
Both have made a huge impact during the past five months. Acuna topped all Minor Leaguers with 181 hits and was one of just two to reach 20 homers and 40 steals. Duplantier posted a 1.39 ERA, the second-lowest among full-season qualifiers in the past 32 years (behind only Justin Verlander's 1.29 in 2005).
In honor of their breakout seasons, Acuna is MLBPipeline.com's Hitting Prospect of the Year and Duplantier is our Pitching Prospect of the Year. Several other blue-chip prospects had fantastic Minor League performances, and we're spotlighting several of them on the MLB Pipeline Prospect Team of the Year. Nominees are determined and voted on by the MLBPipeline.com staff. Players must have spent at least half the season in the Minor Leagues to be considered.
C: Victor Caratini (Cubs' No. 6 prospect)
Triple-A: .342/.393/.558, 83 G, 50 R, 100 H, 27 2B, 3 3B, 10 HR, 61 RBI, 27 BB, 48 SO, 1 SB
Majors: .261/.333/.391, 22 G, 6 R, 12 H, 3 2B, 1 HR, 2 RBI, 2 BB, 10 SO
Caratini was a career .277/.364/.398 hitter entering 2017, so his breakout was unanticipated. He's now the best position prospect in a Cubs system that has promoted several studs to the Majors and traded others, and he hasn't looked out of place in his brief big league action. A second-round pick by the Braves in 2013, Caratini came to Chicago a year later in a trade for Emilio Bonifacio and James Russell.
1B: Rhys Hoskins (Phillies' No. 6 prospect / MLB No. 69)
Triple-A: .284/.385/.581, 115 G, 78 R, 114 H, 24 2B, 4 3B, 29 HR, 91 RBI, 64 BB, 75 SO, 4 SB
Majors: .296/.410/.704, 28 G, 23 R, 29 H, 4 2B, 12 HR, 27 RBI, 17 BB, 21 SO
Hoskins is the lone repeater from our PTOY in 2016, when he ranked second in the Minors with 38 homers and third with 116 RBIs. The 2014 fifth-rounder continued to raise his profile this year by winning International League MVP and Rookie of the Year honors after pacing the league in on-base percentage (.385), slugging (.581), OPS (.966) and RBIs (91). No Minor Leaguer can top Hoskins' 67 homers and 217 RBIs over the past two seasons -- and no big leaguer had ever hit 11 homers in his first 18 games before Hoskins did so this summer.

2B: Scott Kingery (Phillies' No. 3 prospect / MLB No. 55)
Double-A/Triple-A: .304/.359/.530, 132 G, 103 R, 165 H, 29 2B, 8 3B, 26 HR, 65 RBI, 41 BB, 109 SO, 29 SB
After homering just five times in his first full pro season in 2016, Kingery boosted his power production and became the only Minor Leaguer to record at least 25 homers and steals. He's the only middle infielder in at least the past 30 years to do so. With Yoan Moncada and Ozzie Albies about to graduate from rookie/prospect status, the 2015 second-rounder will become the top second-base prospect in the Minors.
3B: Rafael Devers (Graduated from Red Sox's Top 30)
Double-A/Triple-A .311/.377/.578, 86 G, 54 R, 100 H, 20 2B, 3 3B, 20 HR, 60 RBI, 34 BB, 63 SO
Majors: .290/.351/.507, 37 G, 22 R, 40 H, 6 2B, 8 HR, 18 RBI, 13 BB, 38 SO, 3 SB
Despite being the youngest regular (age 20) in the Eastern League, Devers might have won the Double-A circuit's batting and slugging titles had the Red Sox left him there all season. Instead, they promoted him to Triple-A in mid-July and called him to Boston nine days later. Devers leads the Sox with eight homers since his arrival, justifying the faith the organization showed when it signed him for $1.5 million out of the Dominican Republic in 2013.

SS: Bo Bichette (Blue Jays' No. 2 prospect / MLB No. 29)
Class A/Advanced Class A: .362/.423/.565, 110 G, 88 R, 162 H, 41 2B, 4 3B, 14 HR, 74 RBI, 42 BB, 81 SO, 22 SB
The son of four-time All-Star Dante Bichette, Bo batted .427 in 22 games in Rookie ball after signing as a second-round pick a year ago. He was even more impressive in his first full season, flirting with .400 and winning the MVP award in the pitcher-friendly Midwest League, making the jump to Class A Advanced at age 19 and becoming the first teenager to win the Minor League batting title since Gil Torres in 1966. Bichette also finished second in the Minors in OPS (.988), third in on-base percentage (.423) and fourth in doubles (41).
OF: Ronald Acuna (Braves' No. 1 prospect / MLB No. 7)
Advanced Class A/Double-A/Triple-A: .325/.374/.522, 139 G, 88 R, 181 H, 31 2B, 8 3B, 21 HR, 82 RBI, 43 BB, 144 SO, 44 SB
Signed out of Venezuela for a mere $100,000 in 2014, Acuna flashed five-tool ability but a broken thumb marred his full-season debut in '16. For more on him, read Jonathan Mayo's Hitting Prospect of the Year story.

OF: Derek Fisher (Astros' No. 3 prospect / MLB No. 53)
Triple-A: .318/.384/.583, 84 G, 63 R, 109 H, 26 2B, 1 3B, 21 HR, 66 RBI, 34 BB, 74 SO, 16 SB
Majors: .219/.322/.371, 36 G, 14 R, 23 H, 2 2B, 1 3B, 4 HR, 13 RBI, 14 BB, 36 SO
A supplemental first-round choice in 2014, Fisher posted 20-20 seasons in his first two full years a pro and was on pace to do so again this summer before big league callups got in the way. His .967 OPS ranked sixth in the Minors and second among players on this PTOY, trailing only Bichette's .988. Fisher homered three times in his first 11 games with the Astros and got a five-week run as their regular left fielder before slumping.
OF: Austin Hays (Orioles' No. 2 prospect / MLB No. 97)
Class A Advanced/Double-A: .329/.365/.593, 128 G, 81 R, 172 H, 32 2B, 5 3B, 32 HR, 95 RBI, 25 BB, 85 SO, 5 SB
Majors: .000/.000/.000, 1 G
As a college performer with tools and a chance to play up the middle, Hays probably shouldn't have lasted 91 picks in the 2016 Draft. He became the first player from that class to reach the Majors, starting 2017 in Class A Advanced and getting his first at-bat with Baltimore on Thursday. In between, Hays led the Minors in total bases (310) and placed second in homers (32) and extra-base hits (69).
DH: Vladimir Guerrero Jr. (Blue Jays' No. 1 prospect / MLB No. 5)
Class A/Advanced Class A: .323/.425/.485, 119 G, 84 R, 141 H, 28 2B, 2 3B, 13 HR, 76 RBI, 76 BB, 62 SO, 8 SB
Guerrero and Bichette played together at two Class A stops this year, generating countless headlines because they're elite prospects well advanced beyond their teenage years and the sons of former stars. At age 18, Guerrero placed second in the Minors in on-base percentage (.425) and walked more than he struck out. He resembles his father, likely a future Hall of Famer, with his upside as a hitter, and is making his $3.9 million bonus out of the Dominican in 2015 look like a prudent investment.

LHP: Luiz Gohara (Braves' No. 8 prospect / MLB No. 91)
Class A Advanced/Double-A/Triple-A: 7-4, 2.62 ERA, 26 G, 25 GS, 123 2/3 IP, 106 H, 6 HR, 44 BB, 147 SO, .228 AVG, 1.21 WHIP
Majors: 0-1, 13.50 ERA, 1 G, 1 GS, 4 IP, 4 H, 1 HR, 4 BB, 6 SO, .267 AVG, 2.00 WHIP
Gohara became one of the Mariners' best pitching prospects immediately after signing for $880,000 out of Brazil in 2012, but he also frustrated the organization with repeated off-field issues. Traded to the Braves for Mallex Smith and Shae Simmons in January, he jumped all the way from Class A Advanced to Atlanta in 2017. Interestingly, both Gohara's ERA (1.98 to 2.60 to 3.31) and his strikeout rate (9.7 to 10.4 to 12.2 per nine innings) increased every time he moved up a level in the Minors.
RHP: Jon Duplantier (D-backs' No. 2 prospect)
Class A/Advanced Class A: 12-3, 1.39 ERA, 25 G, 24 GS, 136 IP, 91 H, 6 HR, 42 BB, 165 SO, .192 AVG, 0.98 WHIP
Duplantier went two picks before Hays in the 2016 Draft, sliding into the third round because of health concerns after he missed all of the previous season at Rice with a shoulder injury that didn't require surgery. For more on him, check out Mike Rosenbaum's Pitching Prospect of the Year feature.

RP: John Curtiss (Twins' No. 19 prospect)
Double-A/Triple-A: 2-0, 1.28 ERA, 39 G, 19 SV, 49 1/3 IP, 23 H, 0 HR, 22 BB, 68 SO, .135 AVG, 1.08 WHIP
Majors: 0-0, 10.80 ERA, 4 G, 0 SV, 3 1/3 IP, 5 H, 1 HR, 2 BB, 4 SO, .333 AVG, 2.10 WHIP
A 2014 sixth-rounder, Curtiss took off once the Twins made him a full-time reliever in the middle of his first full pro season. Now operating with a harder fastball and slider, he allowed fewer hits per nine innings (4.2) than any pitcher who worked as many as his 49 1/3 innings this year. Curtiss didn't allow a hit in 20 of his 39 Minor League outings while converting 19 of 20 save opportunities.