With less than two weeks remaining in the regular season, it’s increasingly apparent that the Chicago White Sox will relinquish their World Championship without a postseason fight. Through Wednesday, the Sox are running third in the AL Central, six games behind the slumping but still division-leading Detroit Tigers and 5.5 behind the Wild Cardleading Minnesota Twins. Baseball Prospectus’s Postseason Odds report — which uses a team’s run-scoring and run-preventing proclivities, adjusted for park effects and quality of competition, in a Monte Carlo simulation which plays out the rest of the season 1 million times — gives the Sox a mere 3% shot at reaching the playoffs. The Twins, on the other hand, are at 97.6%, the Tigers at 99.4%.

As September dawned, the Sox and Twins were running neck-and-neck for the Wild Card, apparently the only postseason vacancy remaining in the AL. Chicago held a half-game lead, but the Odds report showed both teams holding a 50% shot of reaching October, either via the Central crown or the Wild Card. The remaining schedules favored Minnesota, with three more home games than the Sox and thehome-field advantage for a season-ending three-game series between the two clubs; at the imposing Metrodome, the Twins had gone 45–22.

Nonetheless, conventional wisdom showed reasons to favor the Sox. Not only did they have experience and the championship imprimatur on their side, they held a significant advantage at the training table.

In August, the Twins suffered a pair of devastating blows to their rotation. Brad Radke, who’d battled a torn labrum all season, left his August 25 start against Chicago after just two innings and was subsequently discovered to have a stress fracture in his shoulder. Worse, rookie Francisco Liriano, arguably the best pitcher in the league this year (even better than teammate Johan Santana), was limited to one start in August because of elbow soreness. By comparison, the defending champs were fairly healthy, save for a recent hamstring injury to slugger Jim Thome and intermittent problems with Joe Crede’s back.

Yet the Sox are the ones who unraveled. Despite the Twins’ injuries — Liriano is done for the year after an abortive return, while Radke may get one more start — Minnesota has raced to a 13–6 record this month, while Chicago has stumbled along at 7–12. What happened?

For starters, the health problems of Thome and Crede have sapped the duo’s productivity. On August 23, after Thome suffered the strain, manager Ozzie Guillen termed it “not a big deal.” But after sitting a week, the 36-year-old slugger hit just .222 AVG/.394 OBP/.407 SLG over the next three; a pair of homers this past Monday and Tuesday suggest he’s only now regaining the form which helped him swat 39 roundtrippers pre-injury. Crede was poised to join Thome and teammates Jermaine Dye and Paul Konerko in becoming the 11th team to feature a quartet of 30-homer hitters after he hit number 29 on September 1. Since then he’s struggled, batting a homerless .173/.283/.211 and missing three games because of lower back pain. Through Tuesday he was mired in an 0-for-22 slide.

Additionally, lead-off hitter Scott Podsednik hasn’t been able to shake his season-long funk. Last year,”Podzilla” hit .290/.351/.349 with 59 steals despite missing half of August with a groin pull. This year, he’s slipped tom .261/.332/.353 with 40 steals, and has failed to get an extra-base hit in September, scoring just four runs.The frustrated Guillen briefly dropped him from the leadoff spot and lately has platooned him with Pablo Ozuna. In all, the potent Sox offense has suffered, scoring 4.16 runs a game, 36% below their pre-September average of 5.65.

The team’s bullpen — a major strength last year — has stumbled lately as well.Though the Sox have allowed a respectable 4.53 runs a game this month, Guillen’s club, like Jimi Hendrix in “All Along the Watchtower,” can’t get no relief. The bullpen has yielded an abominable 6.58 ERA in September while walking 5.71 hitters per nine innings. Closer Bobby Jenks, whose hefty frame has caused hip troubles, coughed up runs in four straight appearances — blowing two saves and taking a loss before missing a week. His ERA for the month stands at 10.12. Setup man Brandon McCarthy, with a 19.29 ERA, has been worse. Since tossing a season-high 5.1 innings in relief of a battered Jose Contreras on August 26, he’s been scored upon in six out of seven appearances; the Sox won only one of those games, and that despite his inability to retire a single batter that day.

Overall, the Sox bullpen ranks just ninth in the league in a BP metric called Reliever Expected Wins Added (WXRL), which measures the increment by which a pitcher 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 those early in the game, in blowouts, or with no one on base. Last year, the Sox totaled 12.77 WXRL, second only to the Angels; this year, they’ve managed just 5.62, less than half of the league-leading Twins’ 14.17.

In the winter, general manager Kenny Williams earned praise for his efforts to upgrade the World Champions. He traded centerfielder Aaron Rowand, a defensive wiz, and two prospects to Philadelphia for Thome, and sent three players — starter Orlando Hernandez, reliever Luis Vizcaino, and centerfield prospect Chris Young to Arizona — for starter Javier Vazquez. Bad hammy and all, Thome has paid off, and Vazquez has been adequate if unspectacular, with a 4.70 ERA that’s fourth-best among the five Sox starters. But centerfield has been a nagging problem; rookie Brian Anderson, though excelling on defense, has hit just .231/.301/.368.Young,18 months younger but more highly regarded, was recently promoted to the bigs and has hit .259/.339/.444 after missing much of the year with a fracture in his hand.

Williams shored up the bullpen inseason by acquiring David Riske (3.58 ERA) from Boston and Mike MacDougal (1.90 ERA) from Kansas City, but he reportedly passed up a deal to acquire Washington’s Alfonso Soriano, who recently reached the 40-homer/40-steal milestone, because of his unwillingness to part with McCarthy. Given the team’s high-powered offense and Mc-Carthy’s bright future (BP rated him the majors’ 23rd-best prospect prior to 2005), that decision is defensible. But right now, Soriano’s speed and power — and the flexibility to replace Podsednik in leftfield or slot him in center to replace Anderson — look like a perfect prescription for what ails the Sox.Their failure to fulfill it may deprive them of a chance to repeat as champions.

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