Over the weekend, Frank Thomas, despised former member of the Chicago White Sox, gained a measure of revenge on his former employer. Thomas, Chicago’s all-time best hitter, has been the subject of a persistent Stalin-style campaign by Sox manager Ozzie Guillen to recast him as a villain. With the White Sox struggling to catch the Twins in the AL Wild Card race, Guillen’s personal Trotsky drove in seven runs on two homers and a double to help the Oakland A’s send the White Sox to three straight losses.

Thomas’s series was all part of a terrific, career-reviving second half (.322/.413/.617) and an even more spectacular September (.344/.379/.869, 10 home runs in 61 at bats through Sunday). With Thomas’s help the A’s have gone 30–12 since the end of July and extended a slim 1.5 game lead to a safe seven games.

This surge has sparked talk that Thomas deserves some MVP award consideration, but a more appropriate recipient of an award for Thomas’s season might be the man who took a chance on signing him despite his 38 years of age and two consecutive seasons mostly lost to injury, A’s general manager Billy Beane.

The derby for the title of baseball’s executive of the year, formal and informal, is a tight one. New York’s GMs, Brian Cashman of the Yankees and Omar Minaya of the Mets, are having strong seasons, with both teams boasting the best records in their respective leagues. Cashman hung fire when Gary Sheffield and Hideki Matsui got hurt, holding out for a sweetheart deal for Bobby Abreu rather than biting on some of the lesser, Reggie Sandersstyle outfielders being urged on him.

His off-season deal for Johnny Damon has also paid dividends for the Yankees.The outfielder has put together one of the best seasons of his career, though the length of the contract — the stumbling block that kept the Red Sox from aggressively bidding—may yet haunt the Yankees. There is little chance that Damon will be a valuable center fielder in 2009. That, however, may be a consideration outside the narrow bounds of this year.

Minaya’s plans for the Mets have obviously paid off, though it remains to be seen if he has overreached in places. Dealing Xavier Nady for 16.1 innings of Roberto Hernandez (so far) and the salvage rights to Oliver Perez might have been an overreaction to the Duaner Sanchez accident and adding Shawn Green handcuffs the Mets to a ship that is not sinking but sunk.

Less equivocal were Minaya’s various moves for pitching. The Kris Benson for Jorge Julio deal, a trade that initially seemed to hurt the Mets more than it helped, was improved when Minaya later spun Julio to Arizona for Orlando Hernandez. John Maine, seemingly a throw-in on a deal designed to improve the bullpen and reduce the Benson family presence on the team, turned out to be a key starting pitcher. Hernandez won’t be with the Mets long, but at 25 Maine could help them for years.

The off-season acquisitions of Carlos Delgado and Paul LoDuca have worked out well, and Minaya has also had his share of good luck in constructing his bullpen behind Billy Wagner (another off-season signing), something that has eluded other GMs, like Mark Shapiro of the Indians or Wayne Krivsky of the Reds, who have tried every reliever this side of the late Wilcy Moore without notable success. There isn’t any inherent reason why, say, a Pedro Feliciano should succeed where a Kent Mercker fails, or a Guillermo Mota should crash and burn on the shores of Lake Erie but thrive in Flushing. To paraphrase Donald Rumsfeld, bullpens happen. The Mets have been the beneficiaries of pitching providence.

Rightly or wrongly, the New York general managers will only get partial credit for their higher profile moves because their superior revenue streams allow them the flexibility to paper over their problems with money. That puts the spotlight on the teams that have to be more creative. Dave Dombrowski of the Tigers revived his team thanks to a productive minor league program and a lot of patience. Larry Beinfest of the Marlins had to trade away his stars, but made sure the deals brought back tons of pitching and a Hanley Ramirez or two. Kevin Towers of the Padres made wise deals for nearly roughly a half-dozen players.

Conversely, the Twins had to get over some of Terry Ryan’s poor off-season additions, such as Tony Batista and Rondell White, before they could actually contend.

The focus, then, comes back to Beane of the A’s. During his run the A’s have always been close, but since Jason Giambi left, they have missed having a pure slugger in the middle of their order. Eric Chavez wasn’t quite that player. Frank Thomas is. By adding the one, last piece of the puzzle — the one dismissed by so many others, including his former team — Beane might have outdone his 29 peers.

Mr. Goldman writes the Pinstriped Bible for www.yesnetwork.com and is the author of “Forging Genius,” a biography of Casey Stengel.