Cesar Puello was going to be one of the breakout prospects of 2011, at least according to some scouts who watched the young Mets outfielder last year.

Puello, 20, has plenty of tools. He runs well, throws well, shows plenty of raw power in batting practice and overhauled a swing that helped him hit .292 with a .375 on-base percentage last year at low Class A Savannah.

Instead, Puello's season started with a thud, as he hit .242/.297/.350 in 64 games heading into the all-star break. Since then, Puello has been one of the best hitters in the Florida State League. After going 2-for-4 with a double, a walk and a stolen base yesterday, he's hitting .290/.350/.475 in the second half (48 games), with 19 stolen bases on the season. He's also clubbed nine home runs after hitting only one last year.

Puello's approach is still raw, but he's also one of the youngest players in the FSL. The Mets have also tried to give him more value by moving him from right field to center field in June, though his reads off the bat will need refinement.

Aaron Hicks, cf, Twins: While Puello has turned it on in the second half, Hicks' season has gone in the opposite direction. Hitting .274/.384/.409 at the all-star break, Hicks has hit just .194/.310/.301 in the second half for high Class A Fort Myers. Yesterday was one of the best games of the season for the 21-year-old, however, as Hicks went 3-for-5 with a triple and a double. Hicks is drawing plenty of walks—his 75 free passes rank fourth in the FSL—but at some point, scouts want to see better overall performance at the plate.

Nolan Arenado, 3b, Rockies: While Hicks has fallen in the second half, Arenado has surged. Arenado went 1-for-4 with his 18th home run of the year yesterday for high Class A Modesto, putting him at .296/.348/.477 on the year. Twelve of Arenado's home runs have come in the second half, and thanks to his dangerous combination of plate coverage and power, he's the rare prospect who has more extra-base hits (51) than strikeouts (50).

Jonathan Singleton, 1b, Astros: Acquired at the trade deadline in the Hunter Pence deal, Singleton has delivered a much-needed, high-upside bat for the Astros. Singleton, 19, went 2-for-4 with a double and three walks in a doubleheader in high Class A Lancaster yesterday. Yeah, the friendly winds of Lancaster have helped him hit .336/.405/.540 in 30 games, but Singleton has done most of his Cal League damage on the road, where he's hitting .365/.437/.651 with all four of his home runs.

Kolten Wong, 2b, Cardinals: Wong's bat has come as advertised, as the 2011 first-round pick delivered a 4-for-4 game with a walk and a stolen base yesterday for low Class A Quad Cities. That's a 10-game hitting streak for Wong, who's managed to squeeze seven multi-hit games into that stretch whlie hitting .343/.405/.508 overall in 43 games.

Jay Jackson, rhp, Cubs: Jackson's season has been a disappointing one, with a 5.40 ERA through 25 starts for Triple-A Iowa. He showed a flash of hope yesterday, however, with 11 strikeouts, two walks (one intentional) and just one run allowed over six innings.

Sonny Gray, rhp, Athletics: The A's have pushed their 2011 first-round pick quickly, but Gray hasn't faced much difficulty yet. The 21-year-old threw five one-hit, shutout innings for Double-A Midland with one walk and three strikeouts. Gray has yet to allow a run in four Double-A starts—a stretch of 16 1/3 innings—while strikeout out 15, walking three and keeping the ball on the ground.

Matt Szczur, cf, Cubs: Szczur is one of the best athletes in the minors, but he's shown this year that he's more than just raw tools. He has faced an adjustment period since his promotion to high Class A Daytona, but he went 4-for-6 with a home run in a doubleheader yesterday, bringing him to .290/.332/.420 with 10 home runs and just 48 strikeouts in 108 games between Daytona and low Class A Peoria.

George Springer, cf, Astros: It's only been five games, but the Astros' first-round pick from this year has played well in his first five pro games with short-season Tri-City. Springer went 2-for-5 with a pair of doubles and a walk yesterday, and he's now 5-for-18 (.278) with four extra-base hits, two walks and only one strikeout in five games while going 4-for-4 stealing bases.