Trevor Bauer, RHP, Diamondbacks (Triple-A Reno)
Bauer's four-game big league stretch in the middle of the season did not exactly go as planned. The third overall pick from 2011 allowed 28 base runners over 16 1/3 innings while averaging nearly 20 pitches per frame. The most frustrating part of Bauer's time—as well as much of the first half of the season—was his lack of aggression. Bauer has the stuff to get hitters out in the zone but, more often than not, he's trying to make the perfect pitch on the corner or trying to get hitters to chase. He seems to have gotten the message of late, as not only did he strike out a career high 12 batters on Friday during a complete game five-hitter, but he did it using just 102 pitches. If the lesson has been learned, there's nothing to be concerned about with those first four big league starts.
Jesse Biddle, LHP, Phillies (High-A Clearwater)
A first-round pick in 2010, Biddle pitched well in 2011, but he did so while showing a concerning drop in velocity. His high school velocity has returned this year to its 90-94 mph range, and Biddle had the best start of the weekend, and one of the best of the year, striking out 12 on Friday night over seven no-hit innings while walking two. Beyond the fastball, Biddle's curveball continues to make progress, as he's begun to harness the pitch in terms of throwing it more for strikes, and his changeup projects to average. As a 20-year-old with 137 strikeouts over 129 2/3 innings at High-A, he's ahead of the curve age-wise and has all the makings of a future mid-rotation workhorse.
Tyson Gillies, OF, Phillies (Double-A Reading)
Gillies was once a highly-regarded prospect who blew away scouts with his speed in the 2009 Futures Game and went from Seattle to Philadelphia in a December trade that year that involved larger names like Cliff Lee and Roy Halladay. Since then, he kind of fell off the map, playing just 31 games combined during 2010 and 2011 because of constant hamstring issues and a disturbing arrest for cocaine possession that saw charges ultimately dropped due to clearly shoddy police work, as Gillies maintained his innocence and never tested positive. While he missed a good chunk of this season with a concussion, his hamstrings have held up and he's been productive, going 7-for-13 over the weekend to lift his season averages to .294/.367/.440 in 54 games. He's not the burner he once was, but still has plenty of speed, although he's stolen just eight bases this year. He'll need to do something more than hit for average, as he'll never be a big power guy, and he's not much of a walker. For now, it's just nice to have the 23-year-old back after falling off the radar.
Erik Johnson, RHP, White Sox (High-A Winston-Salem)
Johnson didn't start the year as a good story in the White Sox system, as last year's second round pick missed the first two months of the season with shoulder issues. The 22-year-old is quickly making up for lost time though, as with a career-high ten strikeouts on Friday night over six innings, he now has a 2.05 ERA over 83 1/3 innings with 77 strikeouts across two A-level affiliates. Johnson is a big, physical power pitcher with an easy plus fastball, and his slider has proven to be a weapon against right-handers that he'll throw at any point in the count. His changeup, however, still has plenty of room for improvement. He's thrown more strikes than expected, should be at Double-A next year, and is suddenly one of the more interesting starting pitching prospects in the system.
Corban Joseph, 2B, Yankees (Triple-A Empire State [Scranton/Wilkes-Barre])
A fourth-round pick in 2008 out of a Tennessee high school, Joseph isn't the biggest or most toolsy guy in the world, but he's been a consistently good hitter who has suddenly added a bit of power to his game to make him all the more interesting. With an 8-for-13 weekend that included home runs on Friday and Saturday, the 23-year-old is hitting .268/.369/.489 in 72 games since moving to the International League at the start of June. His batting line features 46 walks against 276 at-bats, as well as 12 home runs and 35 of his 74 hits going for extra bases. As a second baseman who lacks the speed and/or arm strength to play on the left side of the infield, he obviously has no future in the Bronx, but that has no effect on his prospect stock, which is up significantly.
Seth Maness, RHP, Cardinals (Double-A Springfield)
Maness went eight innings on Friday night, allowing just one run on four hits to lower his Texas League ERA to 2.89 after beginning the year with a 2.15 mark in seven Florida State League starts. He also did something he has don't all year: he walked two batters. That's a new season high, as over the season, Maness has walked a grand total of ten batters over 155 innings. An 11th-round pick in 2011 out of Eastern Carolina University, Maness is certainly one of the most efficient pitchers in the game, as he's currently averaging just 84 pitches per six innings. He's undersized, he rarely touches 90, his secondaries are no more than solid, but you can't argue with the results. How far can you get with just 80 command and control? We'll find out together as Maness is the kind of pitcher a team just keeps moving up until he fails.
Jace Peterson, SS, Padres (Low-A Fort Wayne)
A supplemental first-round pick in 2011, Peterson is difficult to wrap your head around, and reviews from scouts differ greatly. With a 7-for-12 weekend, he's hitting .297/.390/.403 in 104 games, and that comes with more walks (56) than strikeouts (53) in 397 at-bats, as well as 50 stolen bases in 62 games. On paper, he's an athletic but quite raw defender with plus speed, a good approach and a quick bat with little power, and that should be great for a Midwest League shortstop. But he's 22 years old—turning 23 next May—so he's a bit old for the league, and if he moves off the position, his value plummets. He's certainly an intriguing talent, but for every scout seeing a future starting middle infielder, there's another wondering how his game will work at the upper levels.
Miguel Sano, 3B, Twins (Low-A Beloit)
Sano has had three segments to his season so far. There was a hot start, an ugly run in May/June when he hit just .220, and now the 19-year-old is back to super hot mode, hitting two more home runs over the weekend to lift his season line to .264/.383/.532 which contains a 1022 OPS in 50 games since the All-Star break. With 26 home runs, Sano leads the Midwest League by nine, while also leading the circuit in RBI, extra base hits, total bases and tying for the lead in walks. His raw power has earned a rare 80 score from some scouts, and his plate discipline has been a more than pleasant surprise. His power comes at a cost, as evidenced by 137 strikeouts, and his 41 errors are just a small indication of how little a chance he has to stay at third base. Still, his power is out of this world, and he remains one of the best offensive prospects in the game.
Trayce Thompson, OF, White Sox (Double-A Birmingham)
Nobody has ever questioned Thompson's tools, and there are suddenly some signs that things are clicking for the 21-year-old outfielder. After hitting .301/.353/.526 in 49 second half games for High-A Winston-Salem, Thompson was moved to the upper levels, and despite playing in the pitcher's paradise that is Birmingham, he seems to be thriving, as with home runs on Saturday and Sunday as part of a 6-for-9 weekend, he's 9-for-22 with 18 total bases in his first six Southern League contests. He's a prototypical big, athletic outfielder with plus-plus raw power, a very good arm and enough defense to give him at least a shot at staying in center field, but strikeouts will always be a part of his game, as he's already whiffed 151 times this year in 122 contests. The hope is that he can do enough around those strikeouts to make up for it, but he's unquestionably taken a major step forward this year.
Matt Wisler, RHP, Padres (Low-A Fort Wayne)
Sleeper Alert! Wisler was a seventh-round pick out of an Ohio high school in 2011, but that was more because teams saw him as a difficult sign. He ultimately agreed to a $500,000 bonus, and the 19-year-old (he turns 20 in September) has become a pop-up pitcher in the Midwest League this year. With five shutout innings on Saturday, Wisler has a 2.60 ERA over 104 innings with an impressive 102 strikeouts and just 27 walks, and the scouting reports are nearly as impressive. Six-foot-three, skinny and projectable, Wisler has gained some velocity since signing, sitting in the low-90s with plus command and control, and his curveball has flashed place to give him a second pitch. In what is already a deep system, Wisler has earned easy Top 20 consideration in the upcoming Padres prospect rankings, and even that might be a little light.