The Giants and right-handed reliever Santiago Casilla agreed to a three-year, $15 million deal on Monday, according to a source.
The deal, which also contains a vesting option for a fourth year according to the source, buys out Casilla's final year of arbitration and two free-agent years. According to the source, if Casilla, 32, fails to reach certain thresholds, the vesting option becomes a club option.
Casilla was 7-6 with a 2.84 ERA in 73 regular-season appearances last season. He pitched in two games against Detroit in the World Series, going 1-0 and not allowing a hit in 1-1/3 innings.
The deal was first reported by Henry Schulman of the San Francisco Chronicle.