The rest of the baseball world may be attuned to the July 31 trade deadline, but as the season nears the two-thirds mark, it’s fun to start kicking around candidates for the Most Valuable Player awards. Nobody’s going to claim the hardware without a strong final two months, but by turning to Baseball Prospectus’ advanced metrics — uniquely suited to measuring value — we can spotlight the emerging races.

Before delving too deeply into the candidates, a couple clarifications are in order. First, there’s no official definition of what “Most Valuable” means, but strong precedent favors top players on contending teams. In the past 30 years, only seven MVPs have played for teams winning fewer than 87 games in a nonstrike year, and just three toiled for sub-.500 squads. Teams hovering below .500 still have time to return to respectability, but a player’s chance at the award must be weighed against that likelihood. Second, pitchers are eligible, though they also have the Cy Young award, and the past 30 years have seen just four hurlers — all American Leaguers, three of them relievers — win the MVP, generally in years when no consensus could be reached on the league’s best hitter.

This year, the National League MVP race is simplified by the league’s kittenlike weakness. Thanks to a dismal 98–154 (.389 winning percentage) showing in interleague play, just five of 16 teams have records above .500. Among the top hitters according to Value Over Replacement Player (VORP) — measuring a player’s offensive contribution against that of a bench player or freelyavailable minor-leaguer — just four of the top 15 play on winning teams. Factor in defensive contributions by switching over to the Wins Above Replacement Player (WARP) metric, which converts runs on both sides of the ball to wins, and the field narrows even further.

Until an oblique strain sidelined Albert Pujols for 15 games, the Cardinals’ slugger wasn’t just gunning for a repeat of last year’s award, he was mounting an assault on Barry Bonds’s single-season record of 73 homers, thumping 25 by May 29. His longball pace has slowed since returning, but he’s still hitting an awesome .323 AVG/.435 OBP/.700 SLG with 33 homers, worth 7.7 WARP, before the start of yesterday’s action.

Pujols’s closest challenger among hitters is the Mets’ Carlos Beltran (6.9 WARP). Coming off a disappointing 2005 season, his first since signing a seven-year, $119 million deal, Beltran is finally showing what the fuss was about, hitting .282/.386/.616 with 30 homers and 14 steals. He’s helped the Mets to the league’s best record and a double-digit lead in the NL East standings; through Saturday, BP’s Postseason Odds report estimated their chances of reaching the playoffs at 99.7%. But Beltran’s candidacy may be dampened by chronic knee problems that should curtail his playing time down the stretch and may also drain his stats. The stellar performance of teammate David Wright (4.9 WARP via .313/.387/.563 hitting) could also draw attention away from his candidacy.

Third in the NL rankings is Arizona hurler Brandon Webb, whose 11–4, 2.64 ERA performance has been worth 6.7 WARP.Without him, the Diamondbacks — whose other starting pitchers have compiled a 5.38 ERA — would barely be leading the Pacific Coast League let alone running second in both the Wild Card and NL West races. A nearly identical case can be made for Cincinnati’s Bronson Arroyo: 9–7, 3.20 ERA, 6.2 WARP for the Wild Card-leading Reds, the rest of whose rotation is nearly as abysmal (5.05 ERA).

A final confirmation of Pujols’s supremacy in the NL comes from BP’s Win Expectancy Added stat, which measures the degree by which a player increased (or decreased) his team’s chances of winning in each plate appearance; late atbats in close games or key situations are worth significantly more than at-bats early in the game, in blowouts, or with no one on base.Pujols has totaled 6.81 Wins Added, more than his two closest stickwielding competitors — Bonds at 3.19 and Wright at 3.17 — combined; Beltran is 10th at 2.48. For comparison, Webb and Arroyo rate as closer contenders with 5.78 and 5.06 wins respectively, according to the pitching equivalent, Support Neutral Lineup Adjusted Value Above Replacement.

In the AL, the MVP award is up for grabs, and if WARP rankings are taken to heart, the field is dominated by pitching. Hurlers on contenders occupy six of the top seven spots; the Twins’ Francisco Liriano (7.4) and Johan Santana (7.3) lead the pack, followed by Boston’s Jonathan Papelbon (6.6), who like Liriano is a rookie.Leading the WARP chase among hitters is Cleveland’s Grady Sizemore (6.0), but with the Indians — a hip preseason pick to win the AL Central after a near-miss last year — now 12 games under .500 and 25.5 out, he doesn’t belong in this MVP discussion. A hair behind him is among hitters is the Twins’ Joe Mauer (5.9). He’s hitting .371/.443/.525, topping the league in batting average and helping his team charge into the Wild-Card picture with a 42–19 record since May 19. Not coincidentally, that date marks when Liriano, who leads the league in ERA at 1.96, entered the rotation.

Just behind him in the WARP and batting title races is Derek Jeter (5.6 WARP). With the Yankee offense decimated by injuries to Hideki Matsui and Gary Sheffield, he’s hitting .352/.426/.487 in a season recalling his dominant 1999 campaign. Cleveland’s Grady Sizemore and Travis Hafner rank just below Mauer among hitters, but with the Indians — a hip pick to win the AL Central after a near-miss last year — 12 games under .500 and 25.5 games out, neither belongs in this MVP discussion.

Also in the picture are a pair of sleeper candidates: Chicago’s Jermaine Dye and Texas’s Michael Young. The former, though overshadowed by teammate Jim Thome’s 33 homers, is having a career year (.317/.394/.625, 26 homers) at age 32, a performance worth 5.6 WARP.The latter’s hitting stats (.308/.351/.442) are inflated by his offense-friendly home park, but his stellar defense at shortstop (+18 runs) propels his WARP to 5.5.

No MVP discussion is complete without Boston’s David Ortiz, who leads the majors with 35 homers thanks to a spree of 17 in his last 36 games. Ortiz, runner-up to Alex Rodriguez in last year’s MVP voting, weighs in at an unremarkable 4.6 WARP; as a DH, he’s not adding any defensive value. But true to his reputation as a clutch hitter, he leads the AL in Win Expectancy Added with 4.15, well ahead of closest pursuers Jeter (3.40) and Dye (3.28), not to mention Mauer (2.53). Pitchers Papelbon (5.86) and Santana (5.27) trump that total, however, as do fellow hurlers Justin Verlander (5.22 from yet another rookie) and Roy Halladay (4.65).

Could this wind up as the year of the MVP pitcher in the AL? The odds may be against it, but the stats certainly aren’t. At the very least, they portend fascinating races for the league’s Cy Young and Rookie of the Year awards.

Mr. Jaffe is a writer for Baseball Prospectus. For more state-of-the-art analysis visit baseballprospectus.com.