Jarred Cosart, RHP, Astros (Double-A Corpus Christi)
I tried to temper the excitement of Astros fans when Cosart delivered six nearly flawless innings in his system debut, and now you know why: in start number two, he allowed seven runs while allowing 10 of the 21 batters to reach base in his second go-around. His stuff is remarkable, but the Jekyll and Hyde act continues to be troubling, and there is arguably no pitching prospect in all of baseball with a wider range of future possibilities.
C.J. Cron, DH, Angels (Short-season Orem)
Cron slugged two more home runs on Friday, but he collapsed on a swing yesterday and was diagnosed with a dislocated knee cap. That's not an especially troubling injury, but one is forced to wonder why Cron was playing in the first place. The Angels drafted him in the first round knowing that a shoulder surgery was needed, and Cron proved nothing by hitting .308/.371/.629 in 34 games for Orem, as we all knew the guy could mash. So he hit 13 home runs in 143 at-bats, but by delaying the surgery, there's a greater chance he won't be ready by spring training. A classic bat-only player who can't run or field, Cron would be better prepared for his full-season debut by being healthy, not by spending five weeks crushing pitchers at a level he doesn't belong at.
Derek Dietrich, SS, Rays (Low-A Bowling Green)
The Rays don't make it especially easy to evaluate their prospects as they remain one of the slower developing teams in baseball. With a 7-for-14 weekend that included his 16th home run of the season, the Rays have a shortstop prospect batting .294/.361/.515 in the Midwest League, but just how good is he? A second-round pick last year out of Georgia Tech, Dietrich has the profile of a player would normally spend his full-season debut at High-A, so he's advanced for the level offensively, and as far as tools go, he has nowhere close to the range for short and will likely move to third base down the road; some scouts wonder why he's not there already. He's a solid prospect, but the position and assignment makes him look better than he is.
Grant Green, OF, Athletics (Double-A Midland)
Shortly after playing second base in the Futures Game, Oakland moved their 2009 first-round pick from shortstop to center field, and the returns so far have been positive. While he's been unable to repeat the power surge from last year's California League showing, Green had six hits over the weekend and projects to hit for both average and gap power, and he's taken well to the outfield, showing improved fly-chasing skills as the season has progressed. Green just didn't have the skills for short, and with Jemile Weeks finally healthy and entrenched as the second baseman of the future in Oakland, center is his best fit, both as a player and for the organization.
Robbie Grossman, OF, Pirates (High-A Bradenton)
A 21-year-old outfielder who signed for a big bonus as a sixth-round pick in 2008, Grossman hasn't lived up to expectations, but he's slowly developed into a player that should be a stat-head favorite. With five hits over the weekend, he's up to .289/.424/.430, and while the 94 strikeouts in 111 games are troubling, every other number shines, including 26 doubles, nine home run, 94 walks, and 23 stolen bases. With gap power, a plus arm, a tick above-average speed, and an outstanding approach, Grossman is the kind of player who can beat a team in a variety of ways and deserves more attention.
Brett Jackson, OF, Cubs (Triple-A Iowa)
With two home runs on Sunday, Jackson has hit six in his last ten to raise his Triple-A slash line to .291/.392/.616 in 24 games. That's been enough to create a lot of excitement with Cubs fans, so I'm here to temper that excitement (hey, it's my job). Jackson is among the streakiest prospects around, just as capable of hitting six home runs in ten games as he is of hitting .208 in May and June, as he did this year. Much of that is due to the amount of swing-and-miss in his game as he has struck out 30 times in 86 at-bats for Iowa. With above-average power, speed, and arm strength, Jackson has 20/20 potential as the Cubs’ center fielder of the future, but it's going to come with a low average and plenty of whiffs, leaving him more as a good prospect, as opposed to the savior for all that is ill on the north side of Chicago.
Tyler Matzek, LHP, Rockies (Low-A Asheville)
Matzek has done little but struggle since signing for nearly $4 million out of the 2009 draft, so it was a big story when he left his minor league team for a brief time this year to work with his high school pitching coach in order to find the delivery that led to so much success before turning pro. He had one of his best outings as a pro on Sunday, striking out nine over seven innings while allowing four hits and walking just one batter, and while he remains inconsistent, there is clear progress, and the Rockies organization deserves as much credit as Matzek himself. It takes the kind of open mindedness rarely found in player development to allow a player to go outside the organization for help, and with most teams, Matzek would still be in the tall weeds.
James Paxton, LHP, Mariners (Double-A Jackson)
Pitchers rarely come back sharp after extended draft holdouts, but Paxton has not only been sharp, he's become one of the better left-handed pitching prospects in the game. Pushed to Double-A after finding his stuff in the Midwest League, Paxton continues to improve his command and the consistency of his secondary offerings, and during a ten strikeout performance on Saturday, both his fastball and power breaking ball were easy plus pitches. With that kind of stuff, a frame built for durability, and a 1.97 ERA in the Southern League with 11.5 strikeouts per nine innings, he's on pace to give Seattle yet another power starter at some point in 2012.
Jacob Realmuto, C, Marlins (Low-A Greensboro)
A third-round pick last year out of an Oklahoma high school, Realmuto has converted from an infielder to catcher as a pro, and he's while he's still a rough receiver, he's an athletic backstop with the potential to be a plus defender. He's already good against the running game, throwing out nearly 40 percent of opposing base steals. At the plate, he has a quick bat, a good approach, and the potential to gain more power down the line, posting a line of .282/.351/.412 on the season. For now, he's known as the kid who took Strasburg deep on Sunday, but Realmuto has a chance to be much more than that, as he's a very real prospect who has shown significant improvement throughout the season.
Stephen Strasburg, RHP, Nationals (Low-A Hagerstown)
He threw strikes, he got up to 98 mph with his fastball, and he whiffed four of the eight batters he faced. All in all, it was a successful rehab, but it's come among criticism as to the timing, as some believe that the Nationals would be better served by exercising extra caution and holding their prized young arm back until 2012. That's crazy talk, as Strasburg has completed his rehab, is not ahead of schedule or being rushed in any way, and taking care of the rehab outings (while maybe getting a big league showing or two in at the end of the season) gets them out of the way and lets him begin 2012 fresh. He's still the best young pitcher in the game.