by JEFF MOORE, Dugout Central

Comment

August is a defining month during a baseball season. As the summer heat becomes constant and humid, the long and arduous month is when a season takes shape, teams have their last opportunity to reform, and the true cream rises to the top. With the trading deadline passed and waiver moves difficult, often a team in need of an arm has nowhere to look but down on the farm.

Some teams have more help on the way than others, and while no team wants to be left in a position where it must rely on an untested rookie in a crucial situation, some rookies perform so well upon arrival they force their manager's hand. Some skippers will gamble with their team's playoff chances with players who are not yet old enough to gamble themselves.

For these teams, their rookie pitchers will play a key role in determining their success. Whether in the spotlight due to necessity or preference, these players will have more of an impact than anybody expected at the start of the season.

5. Justin Masterson, Red Sox

Only the fourth native of Jamaica to make it to the big leagues, Masterson performed well enough in a spot start in April and again in May to join the rotation for most of June and part of July. His 4-3 record and 3.67 ERA in those nine starts earned him a spot in the majors, but with no room left in the rotation, the Red Sox moved Masterson to the bullpen, where they had a gaping hole trying to set up for closer Jonathan Papelbon. In eight relief appearances since his transition, Masterson has held opponents to a .205 batting average and struck out more than a batter an inning. After being eased into his new role, four of Masterson's last five appearances have begun in the seventh inning or later. With right-handed hitters batting .174 off of him for his career, the Red Sox seem ready to try Masterson as the right-handed complement to set-up man Hideki Okajima (who has a 0.75 ERA on the season if you discount his horrible July). This gives the Red Sox a formidable 1-2 punch in the seventh and eighth innings.

4. Clayton Kershaw, Dodgers

Kershaw entered Spring Training as a teenager, but he could end the season starting in a playoff game. With his 20th birthday just barely in the rearview mirror, Kershaw was called up to Los Angeles in late May and made eight starts before the All-Star break, going 0-2 with a 4.42 ERA. All in all, that's a nice showing for a kid with only 16 career starts above A ball, but not quite what the Dodgers needed in a pennant chase. After a brief return to the minors, Kershaw has returned to Los Angeles and is back in the Dodgers rotation. His return began with a rocky start in Colorado, but he has followed that up with three straight gems. In his last three starts, Kershaw is 2-0 with 15 strikeouts in 19 IP, and has given up only one earned run. He's lowered his ERA from 5.18 to 3.71. Injuries to some starting pitchers forced the Dodgers to turn to Kershaw earlier in the season. If he continues to pitch the way he has recently, he will force them to keep him in the rotation through October.

3. Chris Volstad, Marlins

Volstad only has 33 2/3 innings under his belt in the major leagues, but his presence in the Marlins' rotation can already be felt. Five starts into his big league career, Volstad already has four quality starts. He is 2-2 in those starts with an ERA of 2.84, giving stabilization to a rotation that has seen 11 different pitchers take a turn. Of those 11 pitchers, only Opening Day starter Mark Hendrickson is over the age of 25, and he hasn't made a start since the All-Star break. Volstad's performance in the past month has given the Marlins a sense of stability in an otherwise unpredictable rotation. Volstad's quality starts are four of only 48 that the Marlins have recorded this season, good enough (bad enough) for 26th in the league. Asking the 6-7, 21-year-old to continue his success might be a lot, but for the Marlins to hang in the tough NL East, they're going to need everything he can give them.

2. Jeff Samardzija, Cubs

Samardzija may be the least likely player on this list to be in his situation, having entered the 2008 season with only a little over one season of minor league experience, and a college career that was interrupted by football. Even at the time of his call-up, Samardzija had recorded only 285 minor league innings, and had done so with a less than spectacular 4.26 ERA and an appalling 1.46 WHIP. He was hardly baffling minor league hitters, striking out only 166 batters in those 285 innings. His recent promotion to Triple-A had been successful however (4-1, 40 Ks in 37 1/3 IP, 3.13 ERA), and scouts loved the electricity in his arm.

The Cubs front office must have seen what Joba Chamberlain did for the Yankees last season and envisioned the same for Samardzija. So far, he hasn't disappointed. Despite being a starter his entire minor league career, Samardzija has been used exclusively in relief upon his Chicago arrival. He has been in the majors only 19 days, but has already made eight appearances, striking out 12 in 11 2/3 innings with a 1.54 ERA and 0.857 WHIP. He also recorded a save in Kerry Wood's absence due to injury. Manager Lou Piniella has shown no fear putting the rookie in key situations (he's pitched almost exclusively in the 7th inning or later), and his success will be a determining factor in how far the Cubs are able to go in the playoffs.

1. David Price, Rays

Yes, it's true: the rookie who might ultimately have the greatest impact on his team's success isn't even a rookie yet. In fact, he was just recently promoted to Triple-A. Price, the first overall pick in the 2007 draft has been nothing but spectacular in his first professional season. Combined at High-A Vero Beach and Double-A Montgomery, Price has an 11-0 record in 15 starts with a 1.87 ERA and 1.01 WHIP. In 91 1/3 innings, the soon to be 23-year-old has struck out 92 against just 23 walks. He makes his first start in Triple-A this week, surely another step toward an impending call-up. Regardless of how the Rays use Price, either as a starter or reliever, barring a disaster in Triple-A or an injury, we'll see him in Tampa this season. If his performances in the minors are any indication of his talent level, he could be just the move the Rays need to put them over the top.