Engel Beltre, OF, Rangers (High-A Bakersfield)
As a 19-year-old, Beltre was overmatched by California League pitching last year, which brought even more attention to some of the non-baseball issues in his game, as he plays with an edge that the optimist would describe as intense, but others might use more colorful language. He gained some national attention this year for starting a brawl with a game-winning home-run trot that included a snail's pace and taunting his opponent, but for the first time since 2008, his play is earning attention as well. He's a true five-tool talent who is finally coming into his own, batting .444 (24-for-54) in his last 14 games and .326/.374/.464 overall, and at 20, he's still young for level, despite the repeat performance.
Joe Benson, OF, Twins (Double-A Britain)
Speaking of tools, Benson arguably has more than Beltre. Benson is faster than the young Ranger, and also has more raw pop. The one problem has always been that he's just not a very good hitter, as he's averaged nearly a strikeout a game during his pro career and is prone to huge slumps. Just such a slump occurred during the first six weeks of the season, which got Benson sent back to High-A, but he's made some adjustments and everything is suddenly clicking. After hitting .294/.375/.588 during his Florida State League stint, he's no longer an easy out in the Eastern League, as after a 5-for-15 weekend that included a pair of home runs, his Double-A line is now sitting at a much healthier .250/.355/.497, as the tools are starting to play.
Danny Espinosa, SS, Nationals (Double-A Harrisburg)
Espinosa entered the year as one of the few bright spots in the Nationals system after Stephen Strasburg. A third-round pick in 2008 from Long Beach State, Espinosa showed power, speed, and the ability to take a walk during his pro debut. However, questions about his core hitting ability moved to the front and center when just one week ago, his batting average sat at a lowly .219. Since then, he's been one of the hottest hitters around, as he racked up seven hits over the weekend and is 13-for-29 (.448) with three doubles and four home runs in his last seven games, and his OPS has gone up over 100 points in the process help raise his line to .249/.339/.436. By the end of the month, he could be a bright spot again.
Dexter Fowler, OF, Rockies (Triple-A Colorado Springs)
Fowler is slowly becoming the Rockies' version of Alex Gordon. He's been sent to Triple-A, but clearly the lesson has been learned and he deserves another shot. In 20 games since his demotion, Fowler has reached base 34 times and scored 22 runs, and he put an exclamation of his showing on Sunday, going 5-for-6 and having a cycle by the fifth inning. At .373/.458/.639, he's got nothing left to prove here.
Jason Kipnis, 2B, Indians (Double-A Akron)
When Kipnis put up some of the most impressive numbers in college baseball last year, scouts had trouble getting past the small frame and the lack of a monster tool, which dropped him to the second round of the draft. After hitting .300/.387/.478 for High-A Kinston, the Indians moved Kipnis up to Double-A in just his first full season, and while adjusting to his new position well, he's also hitting, and the scouts are sitting up and taking notice. With a 5-for-13 weekend that included two doubles and a home run, Kipnis is hitting .355/.444/.645 in his eight games for Akron. More and more he's no longer looking like an experiment but like Cleveland's second baseman of the future.
Aaron Miller, LHP, Dodgers (High-A Inland Empire)
When a hitter puts up big numbers in the Southern Division of the California League, it always had to be taken with a grain of salt. When a pitcher does it, now that's a different story. A supplemental first-round pick last year who dominated the Midwest League after he signed, Miller continues to shine in a much tougher environment. He's allowed one earned run in seven of his last eight starts to lower his ERA to 2.77 while limiting the circuit to a .201 batting average. With a plus fastball/slider combination and a rapidly improving changeup, the scouting reports back up the numbers.
Matt Moore, LHP, Rays (High-A Charlotte)
With a plus fastball and one of the better curveballs in the minors, Moore has the stuff to miss plenty of bats, as evidence by his minor league-leading 176 strikeouts last year. Control has always been an issue for Moore, and it took a step backward early this year, as his ERA ballooned to 6.63 in early June due mostly to far too many free passes. Finally throwing strikes again, Moore has returned to dominance, tying his season high with 11 strikeouts on Sunday as part of a three-start run that has seen him allow just two runs over 19 1/3 innings while striking out 24 and walking a relatively tame six. If he can stay on track, he should return to his status as one of the top southpaw prospects around.
Carlos Perez, C, Blue Jays (Short-season Auburn)
With mid-June comes the short-season leagues, and the opportunity to finally see some names in box scores that we've been waiting for all year. Signed out of Venezuela in 2008 for a bonus of well over $500,000, Perez was considered a potential Gold Glove receiver, but he's spent his first two years in Estados Unidos proving that he can hit, too. After putting up big numbers in the Gulf Coast League last year, the Jays kept Perez in extended spring training to begin the season, but he's hit the ground running in the much more advanced New York-Penn League, going 6-for-11 with three walks in his first weekend for the Doubledays. He's one of the more interesting young catchers in a system just loaded with interesting young catchers.
Martin Perez, LHP, Rangers (Double-A Frisco)
When the Rangers opened the year with Perez at Double-A, nobody really blinked an eye, as despite being just 19 years old, he looked to have both the stuff and the polish to succeed at such a high level. On Friday, he allowed eight runs without getting out of the second inning, raising his ERA to 6.51, and now we can not be so sure anymore. There's some good news here, including 48 strikeouts in 47 innings, and no reports indicating any loss in stuff. At the same time, the polish is all but gone, as he's walked 31 batters over those 48 frames, and observers report that he's clearly scuffling a bit with his delivery. There's no reason to rush the kid, and one could make the argument that if any prospect could survive a demotion, it's Perez, who would still be one of the youngest pitchers around if you dropped him a level.
Keyvius Sampson, RHP, Padres (Short-season Eugene)
A fourth-round pick in 2008 who signed for second-round money, Sampson is a bit undersized for a righty, but he's got pure power stuff, with a fastball that sits comfortably in the low 90s, touches 95 mph, and an absolute hammer of a curveball that already rates as a plus pitch. After striking out five over five innings in a brief showing for Eugene last year, Sampson has returned there this year, and had one of the better season debuts in the Northwest League, whiffing seven over five shutout innings while giving up three hits and walking one. Once a refuge for soft-tossing strike throwers, the Padres' system is suddenly packed with arm-strength guys, and it is a better system for it.