Romo performed very well to begin the 2012 season and did not allow an earned run until May 17, 2012. After Brian Wilson underwent Tommy John surgery in April, Santiago Casilla was given the closer role. Casilla converted 20 of his first 21 save opportunities but blew five of his next nine save situations, posting a 7.71 ERA from June 23 through August 7. Bochy announced on August 7 that the Giants would use a "bullpen by committee" strategy, with Romo, Javier López, and Jeremy Affeldt pitching the final two innings of close games, depending on which hitters they would be facing. Romo and López received most of the save opportunities; Affeldt only had one save after that point. From then through the end of the season, Romo converted nine out of nine save opportunities and posted a 1.33 ERA. Romo appeared in 69 games of the 2012 season, earning 14 saves with a 1.79 ERA, which was fourth among NL relievers and trailed only Craig Kimbrel (1.01), Aroldis Chapman (1.51) and Eric O'Flaherty (1.73). Though he had become the closer by the end of the year, he won the Gibby Award for being MLB's Setup Man of the Year. The Giants won the NL West; in the NLDS against the Cincinnati Reds, Romo appeared in three games, winning Game 3 and saving Game 5. He pitched in all four of the Giants' wins in the NLCS against the St. Louis Cardinals but did not get a single save opportunity. However, in the World Series against the Detroit Tigers, he made three appearances and recorded the save in each of them. He pitched the final inning of the deciding Game 4 and struck out three straight, including Miguel Cabrera for the last out and the Giants' win. In the World Series, Romo pitched three perfect innings and had five strikeouts.