Corey Hart, RF It's up to Hart to play as well as he can the rest of the month, so when he's traded, he'll net more prospects in return, as the Brewers, 8 1/2 games out of the playoffs, are best served to rebuild. It's been a great turnaround for Hart, who didn't start Opening Day and had teammates such as Ryan Braun worried that he might be released in the spring but now leads his team with 21 home runs and 65 RBIs and made the NL All-Star team.
Ned Yost, Manager Since Yost took over for the fired Trey Hillman in May, the Royals have a winning record (27-26), no small feat for a team that was 12-23 before that. Yost has the label of "interim manager" for now, but if he can continue to get the most out of his players, he could be a good fit in the Kansas City dugout beyond this year. And there's no telling with the Royals, but one would assume they'll call up some of their top young talent later in the year -- such as the return of Alex Gordon and the debut of slugging third baseman Mike Moustakos, who was just promoted to Triple A -- so having a good mentor will be important.
Carlos Zambrano, P A pitcher making $18 million ought to be a front-of-the-rotation starter, dependable every five days and a team leader. Big Z, however, was sent to the bullpen in April and then, after being reinstated as a starter, threw a dugout tirade that led to a team suspension and return to the bullpen. At that price and temperament, he's not tradeable and the Cubs can't afford to release him with two more years on his deal, so Zambrano remains an important part of the Cubs and needs to use this second half to reassert himself as a premier pitcher and a cooler head.
Adam Dunn, 1B Dunn is about as consistent as any ballplayer in baseball. Much was made about him hitting exactly 40 home runs for four straight seasons from 2005-08; he also hit 46 in '04, 38 in '09 and is on pace for about 40 again this year. So what matters the most is what he happens to Dunn off the field, as he is in the last year of his contract. Nationals G.M. Mike Rizzo says he'd like to extend Dunn, but one recent report suggested the slugger was growing frustrated with the slow progression of those talks. Losing Dunn -- or trading him if he doesn't seem likely to re-sign -- could set Washington back a year or two in its rebuilding plan.
Roy Oswalt, P Future success for the Astros is predicated on trading their best chip, Oswalt, and restocking the deck with a couple good young players. Much of that will depend on management's ability to find a fair deal, ownership's willingness to relent (Drayton McLane is reportedly reluctant to deal Oswalt, one of his favorite players) and the pitcher's decision of where he'd like to go (he has a full no-trade clause).
Justin Smoak, 1B He has twice the pressure to succeed. As the headlining player of the package received from Texas in exchange for Cliff Lee, Smoak has to prove to he was the club's best option. And no matter how he got to Seattle, he still has to prove he can hit consistently in the big leagues. With the Rangers he had eight home runs in 72 games but batted just .206 with a .311 OBP. It's probably just a slow start, much like he had in Triple-A, where his slash line was .244/.363/.360 in 54 games in 2009 but improved to .300/.470/.540 in 15 games before his 2010 major-league promotion.
Carlos Santana, C Hope is a fickle thing, and Santana is the most exciting young player and best reason for Indians fans to have hope. The young catcher is off to a great start, with a .284/.425/.568 with five home runs and 23 walks in 29 games. First baseman and former first-round pick Matt LaPorta is the runner-up to Santana, as the power-hitter has been on a hot streak since getting re-called from Triple-A, batting .357 with four homers in 12 games.
Derek Hall, President Maybe recently fired manager A.J. Hinch belonged in the front office and was out of his comfort zone as uniformed personnel, but the move to fire general manager Josh Byrnes seemed a bit more impulsive by Hall, considering Byrnes had a contract that ran through 2015. The Diamondbacks underachieved given their star power (Dan Haren, Mark Reynolds, Justin Upton, Chris Young), and now the pressure is on Hall to find a better manager and GM than the ones he had to take advantage of what's in place.
Josh Bell, 3B Bell is not currently on the major-league roster but made a five-game cameo in June to get his feet wet. Acquired from the Dodgers in exchange for reliever George Sherrill, Bell is seen by the organization as the third baseman of the future. Young starters Brian Matusz and Chris Tillman have shown flashes of their ability, and now it's time for another position player to do the same, especially with the progression of catcher Matt Wieters and center fielder Adam Jones having been a bit sluggish this season.
Pirate Parrot, mascot Given the sad state of affairs with the club's play -- it's on pace for the majors' worst run differential since the Cleveland Spiders in 1899 -- the Pirate Parrot, an oversized green mascot, is about the only one who could bring joy to a Pirates fan. Even the Pierogi race was recently tainted (one of the participants was a team employee who was fired after making derogatory comments about the club on Facebook). So for now it's on the mascot, at least until the club's best young prospects -- Pedro Alvarez, Brad Lincoln, Jose Tabata and Neil Walker -- start helping this team win regularly. Pittsburgh entered the break on a six-game losing streak, and its .341 winning percentage would be the franchise's worst over a full season since 1953.