Tim Alderson, RHP, Pirates (Double-A Altoona)
Alderson was once a hot commodity. A first-round pick by the Giants in 2007, the six-foot-six right-hander burst onto the prospect scene by putting up a 2.79 ERA in the California League as a 19-year-old thanks to average velocity and fantastic command, but the velocity began to slip, and his career seemed to go downhill after a trade to the Pirates for Freddy Sanchez. After a six-plus ERA in 2010 and a move to the bullpen last year, he was all but off the radar. Except a funny thing happened this year, as Alderson changed his approach and took up an arm conditioning program that included long-tossing, and this spring his 85-88 mph suddenly jumped to 90-92. After dominating out of the Altoona pen, he moved to the rotation this month, and on Sunday he fired seven shutout innings while allowing just two hits and touching 93; at just 23, and after a Sunday promotion to Triple-A, he's suddenly a prospect again as a potential back-end rotation piece. 

Trevor Bauer, RHP, Diamondbacks (Triple-A Reno)
The Diamondbacks began the year with an elite trio of starters at Double-A Mobile, but with Patrick Corbin in the big leagues and Bauer moving up to Triple-A, only Tyler Skaggs remains in the Southern League. The club wanted to keep their arms out of the high-octane environment of Reno, but Bauer proved that he can more than survive there in his Triple-A debut on Friday, as he struck out 11 over eight innings while walking just one and giving up four hits (one a solo home run by Landon Powell). Bauer isn't just at Triple-A to be challenged, he's there to be geographically closer to the big league club for when the time comes for him to move up.

Dylan Bundy, RHP, Orioles (Low-A Delmarva)
Three innings became four, and are now five. Bundy did it again on Sunday, allowing just one hit over his five frames to keep his ERA at 0.00 over 30 total innings while allowing a grand total of five hits and two walks, all while striking out 40. An American League scout said he did not think Bundy would be challenged until he reached Double-A, but it's clear that Bundy isn't long for the Sally League, as the plan is to have him at High-A Frederick in June, and then who knows where it goes from there. The big leagues are out of the question this year, but he could still get there before his 21st birthday in November of 2013.

Tony Cingrani, LHP, Reds (High-A Bakersfield)
While he's been overshadowed on the Blaze squad by the Billy Hamilton Show, Cingrani continues to dominate, striking out a career high 12 over six innings on Friday to give him 65 over 46 innings, while the one run allowed raised his ERA to 0.78. He certainly has the most eye-popping numbers in the league, but scouts are still mixed as to his future. He's dominating with two plus pitches, the best of which is a fastball that sits in the low-90s, touches 95 and features deception, location and movement. His changeup is a tick above-average with very good arm speed and fade, but scouts have yet to see a quality breaking ball out of him, and as a senior sign who turns 23 in July, it's fair to wonder if one will ever come. He looks like a big leaguer, but despite some of the best numbers in baseball, the role is still to be determined.

Travis D'Arnaud, C, Blue Jays (Triple-A Las Vegas)
Of all the slow starts by prospects in the 2012 season, D'Arnaud's was arguably the most surprising, as we're talking about last year's Eastern League MVP moving to the very friendly confines of Las Vegas. Instead, it took him awhile to find comfort with his swing due to off-season thumb surgery, but he's suddenly looking like one of the best offensive catchers around again; after a 6-for-11 weekend than included three home runs, he has a 1000+ OPS in May and a healthy season line of .297/.360/.514. Despite his on-base struggles, big league catcher J.P. Arencibia is still a valuable commodity for his power alone, but with the first-base slot suddenly open due to Adam Lind's continued struggles, there just might be a way to keep both the incumbent and the top prospect in the end.

Grant Green, OF, Athletics (Triple-A Sacramento)
The A's first round pick in 2009, Green's prospect status took a hit last year with a subpar season in Double-A combined with a move down the defensive spectrum from shortstop to the outfield, but he's getting some of that status back with a strong showing at Triple-A. With a seven-hit weekend that included his fifth home run of the season, Green is now 19-for-42 (.452) in his last 10 games and batting .311/.346/.490 overall. While he's splitting time between left and center, his average speed and arm should work well enough to allow him to play up the middle, as his progress defensively has earned praise from scouts, and with the bat back, he's in line for a 2012 look and potentially a much larger big league role in 2013.

Julio Rodriguez, RHP, Phillies (Double-A Reading)
Rodriguez has always been that other guy no matter where he pitches. Both at Low-A Lakewood in 2010 and High-A Clearwater last year, Rodriguez was surrounded by far more well-known prospects with better stuff, but he was the one always putting up the numbers; now that it's happening again at Double-A, it's time to start taking him seriously. Including his seven innings on Saturday—in which he allowed four hits and struck out seven—Rodriguez has not allowed an earned run in his last four starts, a total of 23 innings that have helped lower his ERA to 1.88. He still just has average velocity, but his all-arms-and-legs delivery creates deception, and his breaking ball and changeup are both solid. With it looking like the upper-levels will not be a hurdle to his unique skill set, Rodriguez finally comfortably has the projection of a back-end starter.

Aaron Sanchez, RHP, Blue Jays (Low-A Lansing)
The Low-A Lansing staff is loaded with prospects, but Sanchez has been the most impressive. With four more shutout innings on Sunday, his ERA is now 0.58. That's in 31 innings so far on the season, in which he's only surrendered 10 hits while striking out 38. Not only have his numbers stood out, but so has his stuff, as his velocity has been in the low-to-mid 90s while touching 97, his curveball has flashed plus and his changeup has made progress. Command and control can still get a bit sloppy due to some mechanical inconsistencies, but on a staff that began the year with more highly rated prospects in Noah Syndergaard and Justin Nicolino, Sanchez is suddenly the one to watch there.

George Springer, OF, Astros (High-A Lancaster)
It took awhile, but it seemed almost impossible for the combination of George Springer and Lancaster to not equal some loud numbers. With an 8-for-14 weekend and five home runs in his last six games, the 2011 first-round pick is hitting .335/.379/.596 in 39 games, but what can we make of it? This is Lancaster. This is where Jon Gaston hit 35 home runs. This is where Koby Clemens hit .345 and where Red Sox fans thought they might have something in Aaron Bats and Bubba Bell, who both had 1000+ OPS in 2007. All we can do is watch the tools, and Springer has plenty of them, but the swing-and-miss is still a concern, and that batting line might be nothing more than him holding serve, really.

Dan Straily, RHP, Athletics (Double-A Midland)
Straily was named a pop-up player in a recent article, and on Friday, he showed why, striking out 15 over seven three-hit innings to give him a total of 69 over 52 1/3 for Midland. That's good for second in all of the minor leagues behind Trevor Bauer, and he's missing bats with three average-to-plus pitches, including a 91-94 mph fastball, and a slider and changeup that both can be plus at times. Most out-of-nowhere pitchers with big strikeout totals are doing it with smoke and mirrors, but Straily is doing it with stuff, and that makes him a very real prospect.