Prospects coming soon to a park near you

June is starting to be referred to as "prospect month." That's the time you start seeing more of the top prospects getting called up, as teams hold back their service time as long as possible. The Royals just promoted third baseman Mike Moustakas to join rookie first baseman Eric Hosmer, the Rockies called up outfielder Charlie Blackmon, and Julio Teheran has made a couple of spot starts for the Braves.

If you're a prospect hound or play fantasy baseball or read the great coverage from Keith Law and Jason Grey on ESPN Insider, you'll know all about the following guys. But if you're a fan who sticks to the majors, this primer will help you learn about some of the top prospects who might soon be ready to make an impact in the majors.

Dustin Ackley, 2B, Mariners

Who is he? Seattle’s first-round pick, second overall, in the 2009 draft.

Keith Law’s preseason top 100: 7.

Stats: .291/.410/.481, 9 HR, 53 BB, 37 SO at Triple-A Tacoma.

After a slow start, Ackley hit .355 with a 1.054 OPS in May and is hitting .350 with a 1.119 OPS in June. He’s got one of the best eyes in the minors and projects as a 20-homer guy in the majors. He was an outfielder and first baseman at North Carolina, and the Mariners have attempted to switch him to second base. However, some scouts believe it’s time to give up on the experiment and move Ackley to left field. Regardless, his bat is ready, and the Mariners desperately need a top-of-the-order on-base guy. Actually, they just need any hitter who can hit something called major league pitching.

Quote: "We view Ackley as our second baseman going forward." -- Mariners GM Jack Zduriencik to The Seattle Times’ Geoff Baker in late May.

ETA: Any day.

Desmond Jennings, OF, Rays

Who is he? A 10th-round pick in 2006, Jennings has been on top-100 prospect lists since 2008.

Keith Law’s preseason top 100: 20.

Stats: .285/.379/.475, 9 HR, 12 SB at Triple-A Durham.

After Jennings' cup of coffee in September, many expected the Rays to hand him their starting left-field job, but the club instead brought in Johnny Damon to play left and Manny Ramirez to DH, with Jennings sent back for a return engagement to Triple-A. After Manny retired, the Rays instead installed Sam Fuld in left (and lately, Justin Ruggiano), content to preserve Jennings’ service time. After hitting three home runs in 109 games last year, Jennings has increased his power output. He’s a little old (24) to be considered a future star in my book but has a nice all-around game and is ready for a major league job.

Quote: "I've been more aggressive towards the ball. Last year, I was tentative in swinging at some pitches, but now I'm feeling good about letting it go and taking an aggressive swing." -- Jennings, last week.

ETA: July. That said, at this point there isn’t evidence to suggest that Jennings could outhit Ruggiano, so the Rays are still in no rush to promote him.

Jason Kipnis, 2B, Indians

Who is he? Second-round pick in 2009 out of Arizona State, moved from center field to second base.

Keith Law’s preseason top 100: 56.

Stats: .293/.366/.489, 7 HR at Triple-A Columbus, over .300 since May.

Kipnis has a nice all-around game with decent pop for a second baseman and baseball instincts that have him 10-for-10 in stolen-base attempts. His move to second base has gone smoother than it has for Ackley.

Quote: "One scout who has seen him multiple times over the past two years noted his improved defense and projects him to be average at the position." -- Kevin Goldstein, Baseball Prospectus

ETA: June. Veteran Orlando Cabrera offers nothing at this point. He’s lost range and is a zero with the stick. The Indians need to call up Kipnis ASAP.

Lonnie Chisenhall, 3B, Indians

Who is he? Cleveland’s first-round pick in 2008 (29th), owner of what Keith Law describes as one of the sweetest-looking swings in the minors.

Keith Law’s preseason top 100: 39.

Stats: .250/.342/.392, 5 HR at Triple-A Columbus.

Chisenhall’s swing hasn’t produced big numbers at Triple-A, and he’s done nothing to alleviate concerns about his production against left-handers, hitting just .175 against them. Even though the Indians could use help at third base -- Jack Hannahan is hitting like Jack Hannahan after a solid April -- Chisenhall’s recall doesn’t appear imminent.

Quote: "Lonnie has been a little more of a challenge. He's had periods where he's been consistent with his swing and approach. He's had other periods where he's struggled a little bit. All the attributes are there for Lonnie to be a very successful major league hitter. He's just a young player developing." -- Indians GM Chris Antonetti to the Cleveland Plain Dealer’s Paul Hoynes on Sunday.

ETA: August.

Matt Dominguez, 3B, Marlins

Who is he? 2007 first-round pick with an outstanding glove but questions about his bat.

Keith Law’s preseason top 100: 55.

Stats: .250/.337/.463, 4 HR in 80 at-bats at Triple-A New Orleans (after fracturing his elbow in spring training).

Dominguez won't turn 22 until August, and the spring training injury set him back a couple of months. As desperate as the Marlins are for help at third base, they’ll undoubtedly want to give Dominguez more time at Triple-A to work on his hitting.

Quote: "His defense is plus-major league defense for a third baseman, and that's his thing. Now he needs to get used to upper-level pitching and get out of here." -- New Orleans manager Greg Norton

ETA: Late July/August.

Brett Lawrie, 3B, Blue Jays

Who is he? Milwaukee’s first-round pick in 2008, the key part of the Shaun Marcum trade in the offseason.

Keith Law’s preseason top 100: 37.

Stats: .354/.415/.677, 15 HR at Triple-A Las Vegas (currently on the DL with a fracture in his hand).

Lawrie was days from a call-up when hit by a pitch on May 31. He’ll be out another couple of weeks before returning to Triple-A. Lawrie had played second base in the Milwaukee system but was moved to third base in spring training. The move has gone well, although some still think he’ll end up in the outfield. He’s made 12 errors at Las Vegas. In other words, he should look like Brooks Robinson compared to Edwin Encarnacion.

Quote: "There's at least a chance he stays at third base, although I doubt it, but he has the arm and athleticism to play a good right field, and in general has made positive changes that have put old makeup concerns about him [to rest]." -- Keith Law, May 31, updated top 25 prospects.

ETA: All-Star break.

Devin Mesoraco, C; Yonder Alonso, 1B; Dave Sappelt, OF, Reds

Who are they? Three Reds prospects at Triple-A Louisville. Prime trade bait.

Keith Law’s preseason top 100: Mesoraco No. 31, Alonso No. 65.

Stats: Mesoraco .330/.409/.558; Alonso .313/.369/.502; Sappelt .333/.402/.543.

Although the Reds are getting solid production from Ramon Hernandez and Ryan Hanigan, they would be reluctant to trade Mesoraco given his terrific Triple-A numbers. (They also have Yasmani Grandal, their first-round pick in 2010, hitting .293 in Class A.) Alonso, blocked by Joey Votto, is more likely to be dealt, but he’s a tier down on the prospect rankings. The Reds have been trying him in left field, but nobody really believes he’s a left fielder. Sappelt is one of my favorite unheralded prospects in the minors. Drafted out of Coastal Carolina, he’s 5-foot-9 and about 200 pounds, so he doesn’t have a classic big league body. But he can hit -- .333 in 27 games this season (he missed time with an oblique injury) and .342 last year (winning the Southern League batting title). The Reds might be content with Chris Heisey in left or use Sappelt as part of a trade offer.

Quote: "He has the potential to be a top-notch everyday hitter and catcher in the big leagues." Louisville manager Smokey Garrett on Mesoraco.

ETA: Trade deadline or later.

David Phelps, RHP, Yankees

Who is he? 14th-round pick in 2008 out of Notre Dame. His fastball rates better than his draft round would indicate, into the 91-93 mph range with good control. He also throws a slider, curve and changeup.

Keith Law’s preseason top 100: Not rated.

Stats: 4-4, 2.95 ERA, 76.1 IP, 76 H, 20 BB, 66 SO, 8 HR at Triple-A Scranton/Wilkes-Barre.

With Bartolo Colon heading to the DL, Phelps might get the call to start on Thursday. He throws strikes and pitches with confidence. Hector Noesi is still the favorite to start, but Phelps was scratched from his Triple-A start on Monday, with Brian Cashman saying they are "preserving all options" for Colon’s slot. Even if he doesn’t make his major league debut this week, Phelps is a good bet to appear at some point this season, considering the fragile state of health and age of the Yankees' rotation. As much as Yankees fans want to see top prospects Manny Banuelos and Dellin Betances, neither is dominating Double-A and both need to refine their command before getting a big league call.

Quote: "Will he make the cover of ESPN Magazine's NEXT issue if he makes two good starts?" -- Yankees fanboy.

ETA: This week?

Trayvon Robinson, CF, Dodgers

Who is he? A local product from Crenshaw High School, Robinson was a 10th-round pick in 2005 and has moved along slowly through the minors.

Keith Law’s preseason top 100: Not rated.

Stats: .304/.363/.567, 14 HR at Triple-A Albuquerque.

The power numbers are impressive, but a lot of hitters are tearing up the PCL this year, and a .304 average actually isn’t all that impressive. Of concern is his 68-to-20 strikeout-to-walk ratio, so although Robinson will turn 24 later this season, he might need a full year of Triple-A. That said, left field has been a problem all season for the Dodgers, and prospect Jerry Sands was just sent back down after struggling in the majors. A natural center fielder, Robinson might be next in line.

Quote: "Will Robinson be the next player in the Dodgers' youth movement to get the call? He went though a stretch in which he was pressing and opening up his swing too much. Still, he's on the club's radar screen for the second half." -- Jason Grey

ETA: July.

Shelby Miller, RHP, Cardinals

Who is he? The 19th overall pick in 2009 out of high school in Texas, Miller might be the top pitching prospect in the minors.

Keith Law’s preseason top 100: 9.

Stats: 3-3, 2.77 ERA, 65 IP, 53 H, 24 BB, 95 SO between Class A and Double-A.

Miller is the long shot on the list, but after dominating Class A for nine starts, he’s been promoted to Double-A and pitched well there in two starts (14 SO in 13 IP). And once you’re in Double-A, the majors aren’t far away. Just 20, he has a high-powered 95 mph fastball, plus an excellent changeup and curveball. The strikeout rate attests to his dominant stuff, but the one concern is he’s been an extreme fly-ball pitcher this year. Although that’s translated to only two home runs allowed in the minors, it’s something to keep an eye on. Miller is unlikely to get the call anytime soon, but with St. Louis in the pennant race, Miller could be a late-season option if needed.

Quote: "Big league hitters don't chase off the plate. They'll chase on the plate below the zone. That's what we're trying to get him to do." -- Springfield pitching coach Bryan Eversgerd to Joe Strauss of the St. Louis Post-Dispatch

ETA: September.

Others to watch: Kyle Gibson, RHP, Twins; Jesus Montero, DH, Yankees; Johnny Giavotella, 2B, Royals; Rex Brothers, LH reliever, Rockies; Matt Moore, LHP, Rays; Mike Montgomery, LHP, Royals.