If there were ever a time for Co-Manager of the Year Awards, it was 2012 in the American League.
Buck Showalter's Orioles were supposed to finish third or fourth. Bob Melvin's Athletics were supposed to finish third or fourth. Showalter's Orioles won 93 games, and reached the postseason. Melvin's Athletics won 94 games, and reached the postseason. And in the process, both managers were forced to remake both their lineups and their pitching rotations.
According to the Baseball Writers' Association of America, Bob Melvin's work was slightly more impressive; he is this year's American League Manager of the Year. The voting was close, with Melvin taking 16 first-place votes, compared to 12 for Showalter. This is Melvin's second award, as he won while managing the Diamondbacks in 2007.
Analytically, the difference between Melvin's and Showalter's seasons comes down to this: Melvin somehow flogged his team to one or the more unlikely comebacks in major-league history, and Showalter managed his team to the greatest-ever record in one-run games.
On the 1st of July, the A's were 13 games out of first place; roughly three months later, they completed their comeback by winning six straight games, including a season-ending victory over their competition for the division title. Melvin also turned over his whole infield, and constructed excellent platoons at first base and in right field. Oh, and near the end of the season he was deploying an all-rookie pitching rotation.
The Orioles, meanwhile, contended all season long on the strength of what eventually became a 29-9 record in one-run games, which was the all-time best winning percentage in such contests.
I find both feats incredibly impressive. But if forced to choose, I choose Melvin because the A's outscored their opponents by 99 runs during the season, the Orioles by only seven runs. Most years, Showalter would have been the obvious answer. But most years don't see a team make up 14 games in the standings in three months.