In the top of the sixth inning Monday night, the Colorado Rockies knocked out San Francisco Giants' starter Madison Bumgarner. They coaxed five walks out of him on the night and cut the Giants' 3-0 lead to 3-2 against him.
The Giants bullpen would let the Rockies get no further. Santiago Casilla stranded the tying run at second base with a strikeout of Yorvit Torrealba to end the sixth before throwing a perfect seventh.
Jeremy Affeldt followed with a scoreless eighth inning. Sergio Romo allowed a leadoff double in the ninth, but then struck out the next three hitters to end the game for his fourth save of the season.
The Giants bullpen combined to throw 3.1 innings of scoreless baseball Monday night. They struck out six of the 11 hitters they faced while only allowing one baserunner. It was a dominant performance that helped vindicate general manger Brian Sabean's decision to invest heavily in the bullpen this offseason.
One of Sabean's first moves of the winter was to re-sign Affeldt to a three-year, $18 million contract. He also gave Casilla a three-year, $15 million extension with a club option for a fourth year. He then finished by buying out Romo's two remaining seasons of arbitration for $9 million.
According to research by Grant Brisbee of McCovey Chronicles, the Giants now have the second most expensive bullpen in the game after Sabean's winter shopping spree. They are eighth in percentage of payroll allocated to the bullpen.
It's sabermetric dogma that it isn't good business to invest heavily in the pen. Relievers can be created out of thin air on the cheap, which saves resources for the rest of the roster.
Romo—a 28th-round draft pick—and Casilla—whom the Giants signed as a minor league free agent—are good examples of why teams shouldn't overpay for relief pitching on the free agent market.
However, Sabean decided that he had to spend some money to keep his three horses off the market. Since Casilla came aboard in 2010, he's put up a 2.25 ERA for the Giants—good for eighth best in baseball among relievers. Romo has the third best ERA at 1.81 during that period. Affeldt's 3.03 ERA since 2010 is pretty good, too.
A large part of their success is due to their ability to pitch effectively against opposite-handed hitters. Over the last three years prior to 2013, Romo has held lefties to a weak .590 OPS, Affeldt has held righties to a .734 OPS and Casilla has held lefties to a .687 OPS (the league average OPS has hovered between .719 and .728 from 2010-12).
The Giants are more dependent on the bullpen than most teams because they play so many tight, low-scoring games in their spacious home ballpark. They absolutely need to win close games in order to make the playoffs because they don't have an explosive offense that can consistently blow the opposition out.
So far this season, Romo and the bullpen have saved leads of 3-0, 5-3, 1-0 and 4-2. Last year, the Giants tied the Reds for the best winning percentage in one-run games by going 30-20. They were 33-22 in one-run games the year before and 28-24 in one-run games on their run to the first World Series title in 2010.
The relief trio of Affeldt, Casilla and Romo has helped the Giants hold on to a lot of close leads on the path to winning two out of the last three World Series titles. Sabean invested heavily to retain them this winter and reward them for a job well done. On Monday night, he looked wise for having done so.
Early in 2013, the Giants' formula for winning looks a lot like it did over the last three years. That means the bullpen is going to be counted on to save a lot of tight games.
So far, Sabean's veterans appear up to the task once more.