Tim Collins, LHP, Blue Jays (Double-A New Hampshire)

If you are not at the very least entertained by Collins, then something is very, very wrong with you. He's a lefty reliever who can get his fastball up to 94 mph with tons of deception, hasn't allowed a hit in his last four appearances, whiffed five of the 10 batters he faced over the weekend, and had struck out 53 in 31 1/3 innings overall while limiting Eastern League hitters to a .190 batting average. Oh, and he's just 20 years old. So why isn't he talked about among some of the top relief prospects in the game? Because he's 5-foot-7, that's why. Actually, that's his listed height, and most think it's a bit kind. Still, production is production, and he's clearly produced at every level, and I, for one, can't wait to see him in the big leagues. 

Matt Dominguez, 3B, Marlins (Double-A Jacksonville)

It's easy to forget that Marlins rookie phenom Mike Stanton was the club's second-round pick in 2007. Dominguez was the first-rounder, and while his development hasn't gone nearly as quickly, we are seeing a trend as he seems to pick it up once he's no longer overshadowed by the big slugger. It was the case last year when Stanton moved to Double-A, and since Stanton moved to the big leagues, Dominguez has suddenly turned it on again, as with three hits and a home run on Sunday, he's slugging .593 in June while adding in his always-outstanding defense at the hot corner. Just because you don't get there when you are 20 doesn't mean you are a bad prospect. Dominguez is going to take a bit longer to develop; the bad news is that with Florida, he'll need to produce as Stanton's teammate.

Didi Gregorius, SS, Reds (Low-A Dayton)

In a system desperate for shortstop prospects, Gregorius is the one to watch. Long and slender, the 20-year-old Dutch native (his family is from Curacao), has plenty of defensive tools, including an arm so strong that he's still trying to figure out how to harness it. He is also an average-to-plus runner with a quick bat who surprises scouts by occasionally driving a ball. At his best of late, Gregorius had six hits and a pair of home runs over the weekend, bringing his season averages up to .286/.337/.416. He's not close to the big leagues, but he's the one shortstop in the system with the best chance of making his mark there.

Kenley Jansen, RHP, Dodgers (Double-A Chattanooga)

With Hong-Chih Kuo healthy, the back of the Dodgers’ bullpen is one of the nastiest in the game. It could get that much nastier down the stretch, as Jansen could be up by September, a fact made all the more remarkable by the fact that the 22-year-old entered the year with just 12 games of professional mound experience. A converted catcher, Jansen is a 6-foot-6, 225-pound beast who sits in the mid-to-upper 90s with his fastball, but unlike many conversion guys, he already has a plus slider as well. Command is still an issue at times, but since his mid-May promotion to the Southern League, opposing hitters are 7-for-49 (.143) with 23 strikeouts against him, including a 3-for-34 (.088) mark by righties. The Dodgers' current financial issues could prevent them from making a move at the non-waiver trading deadline, but Jansen could provide that just-as-valuable internal promotion.

Jeremy Jeffress, RHP, Brewers (Low-A Wisconsin)

On Sunday, Jeffress took the mound for the first time since June 22, 2009, facing three batters and striking out two. No Tommy John surgery or other big injury problems here, as nothing kept Jeffress away from the game other than his own inabilities to stay away from marijuana. His most recent positive test resulted in the 100-game suspension that left him out of the game for nearly a year. With three official positive tests, he's now on his last chance. One more offense involving a drug of abuse, and he's banned from baseball. The 2006 first-round pick still has the best velocity in the system, and arguably one of the better curves, and if he keeps throwing strikes, he could rocket through the system as a short-stint reliever. Plus, maybe the incentive of one more mistake meaning he's thrown it all away could serve as a driving factor. 

Desmond Jennings, OF, Rays (Triple-A Durham)

In the end, talent tends to play, and nobody can claim Jennings isn't talented. With plus-plus speed, good plate discipline, and gap power, some have compared Jennings to a Carl Crawford with walks. While that might be a bit hyperbolic, there was some sense that going into the year, he might be ready enough to let the contending Rays deal Crawford before his impending free-agency with little risk. After a slow start filled with a series of minor injuries, Jennings is finally looking like that Crawford clone again, going 14-for-26 with four doubles and three triples to raise his OPS 169 points to .286/.369/.407. Crawford probably isn't going anywhere this summer, but next spring, it will likely be Jennings taking his place in the Tampa Bay lineup.

Mycal Jones, SS, Braves (High-A Myrtle Beach)

A fourth-round pick last June, Jones is one of the toolsiest players in the system, but as a 23-year-old, his baseball skills remain quite raw. His season started out a mess, as he didn't get his batting average at Low-A Rome above .200 until May 20, but then everything suddenly clicked, leading to a 26-for-62 (.419) run that earned him a promotion to High-A. He has above-average speed, the athleticism to stay at the shortstop, and above-average power for the position. The need for him to move quickly due to his age is working out all right, as after a 8-for-15 weekend, he's batting .526 in his first week of Carolina League play.

Jake McGee, LHP, Rays (Double-A Montgomery)

Once one of the top left-handed prospects in the game, McGee has simply never been the same since 2008 Tommy John surgery, and after getting roughed up for five runs over four innings on May 21, his ERA for the Biscuits sat at an imposing 6.66. Since then, he's been on the most-successful run of his post-surgery career, as the one earned run he gave up on Sunday was the first he allowed in his last four starts. The 98 mph fastball from McGee is a thing of the past, but he's still getting up to 94-95 nearly every time out. That is enough for one scout to still characterize his fastball as special, especially for a southpaw, although his secondary offerings remain average at best. If starting doesn't work out, some think he'll dominate out of the bullpen, but either way it's a huge upgrade from where we were on McGee a year ago.

Chris Nelson, SS, Rockies (Triple-A Colorado Springs)

The ultimate tease of a prospect, Nelson was the ninth overall pick in the 2004 draft and had a remarkable pro debut, followed by a poor showing the following year in his full-season debut. Thus began a Saberhagen-like on-again, off-again career with good seasons followed by bad and/or injured ones. After playing just 29 games last year due to wrist problems, a good 2010 was at least predictable, and with two home runs over the weekend, he's up to .317/.382/.533 in 32 games for the Sky Sox. He'll never displace Troy Tulowitzki at shortstop, but as it's an even-numbered year, can't Colorado take advantage of the calendar and give him a look at second base?

 Matt Purke, LHP, Texas Christian University

If you are a Rangers fan, you might want to look away here. The 14th overall pick in the 2009 draft, the Rangers failed to meet Purke's bonus demands, so he went to school, with no hard feelings. Then Purke had a spring that served as a constant reminder of what Texas missed out on. On Friday, he struck out 11 over 7 2/3 innings against (who else?) Texas while allowing just three hits to get the win in what would ultimately be a huge super regional upset that sent the Horned Frogs to Omaha. Now 14-0 with 133 strikeouts in 103 innings, he'll get a shot at setting a school record for wins in his first College World Series start, and as a sophomore-eligible in next year's draft, he'll likely go much higher than 14th