As the dog days of summer roll along, it's only natural to ask which players are moving up and down on the world's only 24/7 sports stock market. Luckily, we're prepared to answer that very question, with another entry in the canon of PROTRADE's weekly market winner and losers:

Shaun Marcum (SP, Blue Jays): Marcum has fared much better in his second season after a rough 14 starts in 2006. He's taken his game to another level of late, winning his last five starts. Over that span he has struck out 26 batters in 32.2 innings and allowed only three free passes. This 25-year-old right-hander has more than solidified his spot in the rotation -- he's become one of the most unheralded starters in the league.

Justin Upton (OF, Diamondbacks): This former No. 1 overall pick reached the majors after only a season and a half in the minors, making his major league debut a month shy of his 20th birthday. This super-prospect has not disappointed and should be a staple in the Arizona outfield for many seasons to come. In his first 11 games he has a .282/.349/.590 line and has already collected seven extra-base hits. Although he has yet to record a stolen base, his plus-speed should translate to plenty when/if the Diamondbacks loosen his reigns on the base paths.

Ryan Spilborghs (OF, Rockies): Spilborghs has burst onto the scene in 2007, smacking 10 home runs in his first 154 at-bats. For those who think that he is simply a product of that thin Coors Field air -- he's batting .315 on the road with six round-trippers. Spilborghs kills left-handed pitching and should be a perfect platoon with Brad Hawpe, although he'll see more time in center as well with Willy Taveras hurt. Due to his hot start, solid plate discipline, newfound power, and success in the high minors, the Rockies need to find a way to get him in the lineup.

Dustin Pedroia (2B, Red Sox): Boston fans could not have been ecstatic when Pedroia mustered just a .191 batting average in 89 late- season at bats in 2006. And his .182 batting average in April certainly couldn't have bolstered their hopes much either. But the Red Sox have been rewarded greatly for being patient with Pedroia, as he has a .354/.417/.483 line since May 1. His ability to get on base has earned him the second spot in the batting order in front of the Red Sox RBI machines.

Alan Embree (RP, Athletics): This left-handed reliever found the fountain of relief pitching youth in 2006 while with the Padres and has enjoyed continued to success in his transition back to the American League with the Athletics in 2007. Embree's stock went through the roof after injuries to Huston Street and Justin Duchscherer landed him the A's closer role. He has not disappointed as batters have posted just a .186/.245/.279 line since he began saving ballgames.

Jarrod Saltalamacchia (C/1B, Rangers): While Mark Teixeira has turned on the power in Atlanta, Saltalamacchia has struggled since he was dealt to Texas. Since joining the Rangers, Salty has batted just .167, has drawn just one walk, and has struck out 14 times. His BABIP of .235 since the trade suggests that he has encountered a bit of bad luck and his numbers at the plate should improve as he gets more comfortable with his new surroundings.

Travis Hafner (DH, Indians): Hafner is another hitter who has had a bit of bad luck at the plate as his BABIP is nearly 50 points lower than his career average. More troubling is his decline in power after hitting 42 home runs in just 129 games in 2006. His isolated slugging percentage is close to a hundred points lower than his career average. After an uncharacteristically slow first half, it seemed as though Hafner could only improve but his second half has been equally poor. He has batted just .223/.315/.383 since the break with only four home runs and 13 RBIs.

Wily Mo Pena (OF, Red Sox): The Red Sox seem to be set on moving on from the Wily Mo Pena era. His impressive displays in batting practice displays could only tantalize Red Sox fans and management for so long. The Bobby Kielty signing should significantly cut into Wily Mo's at-bats -- those that have produced a .218 batting average and more strikeouts than you could care to watch. Fortunately, it seems he'll still be around to put on a show before games. Think Red Sox fans want a Bronson Arroyo trade mulligan?

Mark Kotsay (OF, Athletics): Since his 30th birthday, Kotsay's body and numbers have deteriorated significantly. His games played and batting average have decreased every season since joining the Athletics. Once a defensive stalwart who patrolled center field with reckless abandon, Kotsay is now limited by a lingering back injury that has affected his range. He continues to show good plate discipline but his lack of pop hurts the A's when he is in the lineup.

Fernando Cabrera (RP, Devil Rays): What a difference a year and a half can make. In 2005, Cabrera struck out 29 batters in 30.2 IP, walking only 11, and had a nifty 1.47 ERA to show for it. In 2006 and 2007, Cabrera has K/9 IP eclipsing 10, but has struggled with control. The Indians recently placed the 25-year-old right-hander on waivers, where the Devil Rays were happy to add him to their improving bullpen. Cabrera has yet to join the Rays, but if he does and can reduce his walk rate, he could very well end up being the closer the Devil Rays have been searching for.

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