J.P. Arencibia, C, Blue Jays (Triple-A Las Vegas)
On a scouting level, there’s little not to like about Arencibia. He was a first-round pick in 2007 for a reason, as he’s a big, athletic catcher with well above-average power. An impatient approach has been his undoing at Triple-A, but he’s still capable of going on a hot streak, as he’s 10-for-23 with three home runs over his last five games to raise his triple-slash line to .263/.312/.500. Though 12 walks in 160 at-bats isn’t exactly a ratio to write home about, it is a significant upgrade from previous years, and the homer-happy Blue Jays should be adding another power bat as early as September, as Arenciba remains their long-term answer at the position.

Drew Cumberland, SS, Padres (High-A Lake Elsinore)
Cumberland has played 41 games for the Storm this year, and he’s had multi-hit efforts in 20 of them. Going 8-for-14 with two doubles, a triple, and a pair of home runs in his last four games, he’s now batting .374/.420/.595 and deserves mention as one of the top position prospects in the system. Beyond the hitting ability, Cumberland adds plus speed and solid defense up the middle. The power has been a pleasant surprise, as after hitting three home runs in his first three years, the 21-year-old already has six in the hitter-friendly California League. This is looking more and more like a breakthrough year, and few teams need more offensive help than San Diego.

Desmond Jennings, OF, Rays (Triple-A Durham)
Is it time to be concerned yet? Jennings entered the year as one of the best outfield prospects in the game, and while the oft-injured power/speed player was banged up early in the year, he’s healthy now and doing, well, nothing. Currently mired in a 1-for-20 slump after going 0-for-10 with five strikeouts over the weekend, Jennings’ slash line sits at a lowly .222/.320/.289, as he’s yet to go deep in 90 at-bats. There was some thought in April that Jennings would be so good this year that it would enable to Rays to deal soon-to-be free agent Carl Crawford in July, but that’s seemingly out the window. For now, the Rays just hope Jennings can turn it around and be ready by Opening Day in 2011.

Corban Joseph, 2B, Yankees (High-A Tampa) 
It feels strange to classify any Yankees prospect as a sleeper, but Joseph might be just that. A fourth-round pick in 2008, Joseph is one of the best pure hitters in the system. By going 11-for-21 in his last five games, including yesterday’s game that included four hits and a pair of home runs, Joseph is up to .316/.367/.456 in the Florida State League, a tough place to put up big numbers. Joseph’s bat is by far his best tool, as he has only gap power, average speed, and merely acceptable defense up the middle, but he’s a good enough hitter that it should carry him to the big leagues.

Reese Havens, 2B, Mets (Double-A Binghamton)
With two first-round picks in the 2008 draft, the Mets selected Ike Davis 18th overall, and then four picks later, they selected Havens. What seems like a never-ending run of minor injuries have hindered Havens’ development, but he appears to be finally on the right path. A shortstop in college, Havens moved to second base full-time this year, a far more natural position for him, and in his first six Eastern League games, he’s 10-for-26 with two doubles, a triple, and a home run. He has above-average power for the position and solid on-base skills, and despite Luis Castillo being signed through 2011, Havens could be joining Davis in the big leagues at some point next season.

Ryan Kalish, OF, Red Sox (Double-A Portland)
Kalish had the best game of the weekend in the minor leagues, going 5-for-5 with a double and home run on Saturday, and following that up with a triple and home run yesterday. Now batting .337/.421/.578 in May, Kalish is ready for Triple-A, but his future with the Red Sox is a cloudy one. He’s a good hitter with an excellent approach, solid power, and surprising speed (he’s swiped 13 bases in 14 attempts), and while that combination is enough to project him as a major leaguer, and a good one at that, will it be good enough for the Red Sox? That question remains unanswered.

Brandon Laird, 3B, Yankees (Double-A Trenton)
The Yankees’ version of Kalish might be Laird. A 27th-round pick in 2007 who received a well over-slot bonus of $120,000 to sign, Laird had put up solid but unspectacular numbers leading up to this season, but he’s taken a huge step forward in 2010, going 11-for-21 in his last five games with three doubles, a triple, and two home runs to raise his season averages to .316/.362/.549. Laird’s bat is his only tool, as he’s a below-average runner with solid-at-best defensive skills, and no matter how well he plays, he’s never going to man a corner for the Yankees. Still, he’s a prospect that has taken a step forward, and scouts are taking notice, so he could be a decent trade chip come July.

Andy Oliver, LHP, Tigers (Double-A Erie)
Oliver gained some national attention for his battle with the NCAA over the use of an agent when he was drafted out of high school, but despite never putting up big numbers in college, it was his power arm from the left side that always got the attention of scouts. Nobody likes big guys who throw hard more than the Tigers, who took him in the second round of last year’s draft and gave him an over-slot bonus of nearly $1.5 million. He signed too late to make his debut last year, so it was surprising to see him open 2010 in Double-A, especially considering the fact that his college performances left so much to be desired. After a bumpy April, Oliver has started to really come on, throwing seven innings of five-hit, one-run ball on Friday to lower his ERA to 3.33. He has a 1.77 mark in his last three starts. His low-to-mid-90s velocity is rare enough for a lefty, but he also adds plus command and control to the pitch. His secondary offerings are still works in progress, but with his size, command, and easy delivery, this is too big of a talent to move to the bullpen, and he’ll get the time needed to figure things out.

Mike Trout, OF, Angels (Low-A Cedar Rapids)
I was speaking to a scout a couple of days ago, and he surprised me by saying that Trout might just be the best position player in the minors. That’s an aggressive sentiment that might be a bit strong, but the 2009 first-round pick at least belongs in the team photo. With a trio of multi-hit games over the weekend, the 19-year-old New Jersey native is up to .359/.441/.547 for the Kernels, and there are no weaknesses in his game. He’s hitting, showing surprising power that has some projecting 20-30 home runs annually down the road, he’s drawing plenty of walks, has a reasonable strikeout rate, and has 25 stolen bases in 29 attempts. If you want to nitpick, his arm is average, but everything else about this guy looks like it will be star level, and he might be the steal of the 2009 draft.

Arodys Vizcaino, RHP, Braves (Low-A Rome)
With Randall Delgado and Julio Teheran both dominating at High-A, Vizcaino has seemingly been forgotten about in the trio of big-ceiling righties in the Atlanta system, but the 19-year-old Dominican who came over from the Yankees in the Javier Vazquez deal has started a run of his own. On Friday, he fired eight shutout innings, and in his last three starts, he’s gone 23 2/3 innings without allowing an earned run and compiled a ridiculous strikeout-to-walk ratio of 21-to-0. Pitchers this young with plus to plus-plus velocity and this kind of command are the rarest of the rare, and Vizcaino ranks right up there with the guys getting more attention… for now.