When the Red Sox went into a tailspin last August, the collapse hastened an end to their threeyear monopoly on the AL Wild Card. Confusion reigned, as though birthright and expense guaranteed playoff spots for the AL East’s top two teams, the Sox and Yankees. That breach was filled by a thrilling AL Central race, as Minnesota overcame the upstart Tigers’ early lead and fought off a late challenge by the defending World Champion White Sox. Though the Twins won the division, Detroit’s wild card winners ultimately snagged the pennant.

With the Yankees currently limping along below .500 and nine games behind the sizzling Red Sox, the Central again appears poised to send two teams to the playoffs. This time it’s a four-team race, with the Indians joining the White Sox, Tigers, and Twins. But which two teams will win out? Baseball Prospectus’s Postseason Odds report uses a team’s run-scoring and run-preventing proclivities, adjusted for park effects and quality of competition, in a simulation which plays out the rest of the season one million times. Run the numbers, and the Tribe (67%) and Tigers (47%) have the best shot at October, with both teams’ chances dwarfing those of the Yankees (26%), though both are also well behind the Red Sox (93%).

The Central-leading Indians boast the majors’ most potent offense, scoring 5.6 runs a game. No Indians hitter ranks in the AL’s top 10 in Value Over Replacement Player — a measure estimating how many runs better a hitter is than a minor leaguer or waiverwire pickup at the same position — though center fielder Grady Sizemore, catcher Victor Martinez, DH Travis Hafner, and shortstop Jhonny Peralta all crack the top 20.

Thanks to that offensive core and improved pitching, the Indians are finally delivering on the promise they showed in 2005, when they won 93 games and mounted a late challenge to the White Sox. Last year’s club slumped to 78 wins despite outscoring opponents by 88 runs; a key factor was an abysmal 39–55 record in games decided by three runs or less. The bullpen was the source of many a close loss, but has been upgraded from spectacularly awful to serviceable, helping the team to a 16–9 record in close games, while the rotation has overcome injuries with depth.

No Indian typifies the turnaround better than 23-year-old Fausto Carmona. Shuttled from rotation to bullpen and back as a rookie in 2006, Carmona went just 1–10 with a 5.42 ERA, and blew three saves in a week-long stint as closer. This spring, when Cliff Lee suffered an oblique strain during spring training, Carmona stepped in with three excellent starts out of four. Caught in the numbers game when Lee returned, he shuffled off to Buffalo, but only briefly — Jake Westbrook’s oblique strain prompted a hasty return. Three starts later, including a recent four-hit shutout of the Twins, Carmona leads the staff with a 2.55 ERA and 16.3 VORP, seventh among all AL pitchers.

Neck-and-neck with the Indians are the Tigers. Their chances at repeating last year’s success suffered a blow back in March, when 42-year-old Kenny Rogers underwent surgery to remove a blood clot in his throwing shoulder, sidelining him until July. To replace Rogers, the Tigers bypassed last year’s solid fill-in, Zach Miner, instead anointing Chad Durbin, who in seven seasons had compiled a 6.13 ERA. After struggling early, Durbin has allowed just seven earned runs over his last 30.2 innings, producing three quality starts out of five. He’s not the only substitute pitching in with good work. When blisters recently felled Jeremy Bonderman, the team recalled Andrew Miller, the sixth pick of the 2006 draft. Despite just one start above A-ball, the 22-year-old lefty blanked the Cardinals for six innings on Friday. He’ll likely return to Double-A upon Bonderman’s activation, but he’s now a credible option lest injury or ineffectiveness strike down another starter. Miller may also shift to the bullpen, where the absence of heat-throwing setup man Joel Zumaya looms large. Zumaya tore a tendon in his middle finger and will be sidelined until August, leaving erratic Fernando Rodney (4.71 ERA) as the bridge to closer Todd Jones.

Helping Detroit’s cause is an offense that currently ranks second behind Cleveland’s, notching 5.5 runs a game. Right fielder Magglio Ordonez is hitting .344 AVG/.425 OBP/.650 SLG, trailing only Alex Rodriguez in both slugging percentage and RBI (38). Shortstop Carlos Guillen, perhaps the league’s most underrated player, is batting .327/.402/.510. Despite a slow start, newcomer Gary Sheffield has provided badlyneeded baserunners, helping the Tigers raise their walk rate from once every 13.1 at-bats in 2006 to once every 10.8 this year.

At 4.5 games back, the White Sox have just a 15% shot at October thanks to an offense recalling their “Hitless Wonder” forebears from a century ago. Only the Royals score fewer runs per game than Chicago’s 4.1, and no AL team has lower on-base (.308) or slugging (.371) percentages. Among hitters, only Jim Thome’s VORP is above 6.3, and he’s just returning after an oblique strain that sidelined him for a month. Fellow sluggers Jermaine Dye, Paul Konerko, and Joe Crede have a combined VORP of -7.7. No amount of good pitching can overcome that.

The Twins come in at an astonishingly weak 6% despite a record (20–24) just a half-game worse than the Yankees. Beyond injuries to last year’s batting champ, Joe Mauer (sidelined since May 6 by a quad strain), and Rondell White (limited to just three games by a calf strain), their problems are largely self-inflicted. They’re getting below-replacement level production from the hitter’s positions of left field, DH, and third base, none of which should have been difficult to upgrade this past winter.

That goes doubly for their rotation. Faced with a thin assortment of experienced starters behind two-time Cy Young winner Johan Santana, Minnesota signed journeymen Ramon Ortiz and Sidney Ponson to buy time for youngsters like Scott Baker, Matt Garza, and Kevin Slowey. Ortiz pitched like an ace in April (2.57 ERA), but he’s been beaten like a rented fifth starter in May (11.74 ERA, and less than four innings a start), hardly surprising given his track record. Ponson, the round knight of Aruba’s dinner tables, was dropped after compiling a 6.93 ERA through seven starts. Baker beat the Brewers in his 2007 debut on Saturday, but the Twins’ eight-game deficit may already be too much, even for a team that came back last year from a similar slow start.

As with any race, injuries and depth play a huge part in determining which teams survive. Thus far, the Indians and Tigers have shown themselves up to the task, which is why the odds say they’ll still be with us come October — unlike a certain pinstriped team of local interest.

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