First baseman, Lucas Duda (Mets): When the Mets traded Ike Davis, many fantasy owners went in the wrong direction and chased the newest Pirate rather than picking up his replacement in New York. Duda had flashed power in the past, but he showed much more consistency this season. His month-to-month splits show that the lefty slugger should be a reliable source of homers and RBIs next season.
Second baseman, Dee Gordon (Dodgers): Gordon was arguably this season's best waiver-wire addition, as owners who pounced on him at the beginning of April got the Major League leader in steals. His stolen-base rate declined after June 1, so fantasy owners should set 2015 projections in the 50-steal range.
Shortstop, Danny Santana (Twins): The 23-year-old was not among the most-hyped prospects for the this season, but he hit the ground running after a mid-May recall, and he never stopped racking up base hits. With continued growth, Santana could be good for 15 homers, 30 steals and 90 runs scored next season.
Third baseman, Josh Harrison (Pirates): Harrison started the season as an National League-only type of utility player. But he took off at the beginning of June, and he was a top-five third baseman from that point forward. Fantasy owners can be hopeful that this late bloomer can carry his breakout season into 2015, but Harrison's massive one-year jump suggests that there could be some regression coming.
Outfielder, Charlie Blackmon (Rockies): Along with Gordon, Blackmon was arguably the biggest surprise in the early months of this season. The 28-year-old is knocking on the door of a 20-homer, 30-steal campaign, which was mostly fueled by tremendous numbers in Coors Field. Smart owners will note that Blackmon's ability to hit for power and average tailed off in the second half, which makes a repeat of 2014 seem unlikely.
Outfielder, Corey Dickerson (Rockies): Colorado's outfield was a treasure trove for waiver-wire miners this season. Dickerson barely played in April, and he should still end up with roughly 25 homers, 75 RBIs and 75 runs scored. His monthly splits are balanced, and the Rockies will need to keep Dickerson in a full-time role next season when their veterans return to full health. He should be taken quite early in 2015 drafts.
Outfielder, J.D. Martinez (Tigers): The 27-year-old had two homers and 11 RBIs in the first two months of the season, and his value was so low that he was sitting waivers in many American League-only leagues. Martinez collected 21 homers and 65 RBIs in the final four months of the season, and he powered many fantasy teams to titles. If Martinez maintains his spot as the team's five-hole hitter, he could be a 30-homer, 90-RBI asset next season.
Starter, Garrett Richards (Angels): Richards showed some signs of being a useful starter in the second half of 2013, but fantasy owners were not expecting him to become the ace of perhaps baseball's best team. He finally figured out how to use his excellent velocity to rack up plenty of strikeouts, but his walk rate remained fairly high. Richards should be able to recover from a major knee injury, but some regression is still to be expected next season.
Starter, Tanner Roark (Nationals): Roark was outstanding in a short stint with the Nats in 2013, but he went undrafted in most mixed leagues, as he had to battle for the team's final rotation spot. He does not offer a high strikeout rate, but he uses excellent control to maintain low ratios. Roark should be a solid mid-rotation mixed-league starter next season.
Starter, Collin McHugh (Astros): When McHugh was recalled in April, it was hard for fantasy owners to get excited with a 26-year-old who owned a career ERA over 9.00. But an improved arsenal led to an outstanding strikeout rate and excellent ratios. Such a large breakout at an advanced age makes a repeat seem unlikely, but McHugh showed a positive sign by saving his best work for the final two months.
Starter, Jake Arrieta (Cubs): After failing to develop for several seasons as a member of the Orioles, Arrieta showed some positive signs in the second half of 2013 after a trade to the Windy City. The 28-year-old started his season on the DL, but he was a borderline ace for the final five months. Arrieta's fantasy value could receive another boost next season if the team's young hitters continue to improve.
Starter, Matt Shoemaker (Angels): Shoemaker was nothing more than an average hurler in the first half, but he turned the corner at the All-Star break and went 9-2 with a 1.87 ERA in the second half. The 27-year-old possesses excellent control, and he pitches on arguably the best team in baseball. Shoemaker should be a six-month asset next season.
Reliever, Zach Britton (Orioles): The lefty could not post an ERA under 4.50 in his first three seasons with the O's, working mostly as a starter. With his career at a crossroads, Britton shifted to the bullpen, and by May he was the team's stopper. With 36 saves in 40 chances and a 1.70 ERA, Britton left little doubt that he will be a solid second-tier closer in 2015. Only a mediocre strikeout rate keeps him out of the top tier.
Reliever, Mark Melancon (Pirates): In 2013, Melancon showed that he was one of the best relievers in baseball. In 2014, he showed that he could pitch just as well in the ninth inning. The 29-year-old took over for an ineffective Jason Grilli in May, and he collected 10 saves in that month. Melancon has a great chance to post a 40-save season with a sub-2.00 ERA in '15.
Reliever, Dellin Betances (Yankees): There were so many closers that emerged during the season, but Betances had more fantasy value than almost all of them, even though he collected just one save. The 26-year-old will exceed 135 K's, and his ratios are as good as virtually any hurler. Betances should be active in all leagues next year, even if his role remains unchanged.