With today’s baseball market structure, young players are a necessity for teams to compete. This season has brought us a number of candidates for the Rookie of the Year Awards in each league, with a few foreign imports leading the pack. We can see how well these players stack up using a stat called Value Over Replacement Player (VORP), a measure estimating how good a player is as compared to a minor leaguer or a waiver pickup at the same position.

The Red Sox are loaded with potential award winners, as they signed both Daisuke Matsuzaka and Hideki Okajima from Japan this winter, while also handing Dustin Pedroia the vacant second base job. According to VORP, the top rookie on the Sox this year is Dice-K, who has put together a 13–10 record with an ERA of 3.76, averaging over a strikeout per inning. He’s amassed a 41.6 VORP, tops among all AL rookies thus far. His record would be more appealing to Rookie of the Year and Cy Young, though, if the Red Sox offense was more consistent. Matsuzaka receives 4.5 support runs per start from the Sox, who normally score 5.3 runs per game. Even that number is deceiving, since Matsuzaka’s six starts in May drew 8.5 support runs per game; more likely than not, he has fewer than five runs to work with.

Besides Matsuzaka, Okajima (32.1 VORP) has excelled in the role of setup man for closer Jonathan Papelbon by stringing together scoreless inning streaks and keeping the veteran-heavy Sox pen afloat during rough times. Injuries to Mike Timlin and Brendan Donnelly have caused problems, and the ineffectiveness of J.C. Romero or Joel Pineiro hasn’t helped.

While the Sox lineup includes Julio Lugo and Coco Crisp, Pedroia and his .392 OBP has delivered the most value in the leadoff slot. Pedroia’s VORP (30.6) isn’t as high as his rookie teammates, but he has played above-average defense for a Sox team that hasn’t seen that from its second basemen in years. Only Tampa Bay’s Brendan Harris has crossed the 20 VORP threshold among rookie position players in the league, and he’s just over at 20.3. It would take a Herculean effort from Harris to overtake Pedroia with just a month to play.

Pitchers are leading the American League rookie pack in 2007, as Jeremy Guthrie (36.8) and Brian Bannister (35.4) don’t trail far behind Dice-K or Okajima in rookie pitcher VORP. Guthrie has been a great story for this season, with Cleveland giving up on the former first-round draft pick, and Baltimore — often bereft of valuable pitchers — scooping him up and fixing him. Guthrie has his problems, as he’s allowed 1.2 homers per nine innings for the season, and 2.1 homers per nine since July 1. That’s the sort of thing pitching coach Leo Mazzone has been able to fix. Even if Guthrie continues to struggle down the stretch — his ERA is 4.82 and he’s just 3–3 since July 1 — he will be out of the running for Rookie of the Year, but still relevant in the future.

Bannister may be a different story. He pitched for the Mets for a short time in 2006 before succumbing to injury, and was dealt to the Royals this past offseason. Bannister is third in VORP among rookie starting pitchers in the majors, but much of this is due to luck in his performance. As linedrive rates correlate with hit rates, and batting average on balls in play (BABIP) is better than any other batted-ball rate, a higher line-drive rate for pitchers usually means poorer performance. But despite a liner rate of 18.4%, Bannister has only seen his BABIP rise to .258, whereas it should otherwise be over the .300 mark, right around the league average. Adjusting his opponent’s line of .235 AVG/.288 OBA /.380 SLG for this gives Bannister a line of .280/.335/.395 or so, which would notably increase his ERA. In fact, Nate Silver of Baseball Prospectus has developed a stat that reflects pitcher ERA with luck factored out called “QuikERA.” Bannister’s QuikERA for 2007 is 5.11, a far cry from his actual ERA of 3.28. You can expect Bannister’s future performances to reflect his adjusted numbers more than his current ones, and it may be tough for him to catch Dice-K down the stretch if his luck runs out.

In the National League, the race for Rookie of the Year is not quite as close. The Cincinnati Reds’ Josh Hamilton will surely win the Comeback Player of the Year Award after overcoming drug addiction before entering the majors this year. But his VORP of 22.3 trails Troy Tulowitzki of Colorado, who sits at 29.4 VORP for his impressive .296/.365/.467 year at shortstop for the Rockies so far. The Astros’ Hunter Pence would have likely ranked second in rookie VORP among all senior circuit position players if he hadn’t spent a chunk of time on the DL, holding him down to 28.2 VORP in just 354 plate appearances.

Elsewhere from the freshman hurler class in the NL, the Giants’ Tim Lincecum leads the pack with 24.0 VORP in 130 innings of work. He has struck out 9.5 batters per nine innings pitched, and despite 3.8 walks per nine innings, he has kept hits and runs to a minimum while posting a 3.94 ERA. There isn’t much else to choose from. If Lincecum had been promoted from the minors any earlier, he may now be leading NL rookies in VORP.

The Brewers’ third baseman Ryan Braun represents the partial-season problems that can affect otherwise strong candidates. Braun has dominated opposing pitching this season, with 46.4 VORP in just 362 plate appearances. With an On-Base Percentage Plus Slugging record of over 1000, he’s kept the Brewers offense alive somewhat as they struggle down the stretch, and he’s amassed 49 extra-base hits in just over a half-season of work. Braun can, in part, thank his 84 at-bats against left-handers for his ridiculous numbers, as he’s mashed them to the tune of .464/.540/.988, numbers you expect from a video game (or Barry Bonds). The only sour note regarding Braun is his poor defense at the hot corner, which ranks amongst the worst in the league at third base. But his offense more than carries his glove right now.

Right now, the Rookies of the Year look like Braun and Matsuzaka, as they both lead the pack with some VORP cushion behind them. Time will tell if this holds up. But they also just happen to be the two with the most upside from this solid class of rookies.

Mr. Normandin is a writer for Baseball Prospectus. For more state-of-the-art commentary, visit baseballprospectus.com.