The San Francisco Giants have their own version of the Core Four that has fueled their recent October dominance.
While players with catchy nicknames like the Panda, the Freak and MadBum, and shiny trophies like former NL Rookie of the Year and MVP Buster Posey get most of the accolades, a quartet of relievers has played almost as big a role in putting the Giants in position to win a third World Series title in five years.
Santiago Casilla, Jeremy Affeldt, Javier Lopez and Sergio Romo are among the seven players who have played in all three postseason runs for San Francisco since 2010, providing stability to a role that can be so hard for some teams to fill come October.
"One thing that we have that's kind of nice is we have that continuity," Lopez said. "We've been around each other for, this is now our fifth year together for most of us especially in that back end of the pen. That part's kind of nice. We know what we can do, and we complement each other."
With a win in the World Series starting Tuesday night in Kansas City, the Giants will join the New York Yankees teams led by Mariano Rivera, Derek Jeter, Bernie Williams and Jorge Posada as the only teams in the past 40 years to win it all at least three times in five seasons.
Like those great Yankees teams that won four titles from 1996-2000, the Giants have relied on stellar relief pitching.
"It's nice to have these four guys with their experience and calmness they bring to the bullpen," Giants manager Bruce Bochy said.
Lopez has had a steady role as a left-handed specialist whose submarine delivery is lethal against lefties, and Affeldt is another tough lefty who can pitch longer because he is almost as effective against right-handed hitters.
Casilla and Romo have had their roles change over the years as the Giants are looking to win their third title with a third closer.
Brian Wilson handled the job in 2010 with Romo and Casilla serving as setup men. That changed in 2012 when Casilla stepped into the closer role after Wilson got hurt early in the season.
Casilla didn't last in the role as Romo proved more effective and ended up closing out the World Series by striking out Miguel Cabrera.
Casilla and Romo flopped roles again this year after Romo blew three saves in June.
"We had a lot of success when he was the closer here, and it's not easy sometimes," Bochy said. "But he never said anything, never complained. For a manager, you appreciate that. He wanted to do everything he could to help the team. That's the only way this works."
The four have combined for a 6-1 record with eight saves and a 1.31 ERA over 87 postseason appearances since 2010. Affeldt has gone 18 straight appearances without a run, Casilla 17 and Lopez 15.
With 68 2-3 innings, they have accounted for nearly one-fifth of San Francisco's postseason innings since 2010, and more than the more heralded starters.
"Every time I've been in the playoffs, it seems like bullpens are used to their maximum," Affeldt said. "'Guys have come in in different situations and thrown strikes and come in for guys when maybe we have to come in mid-inning, guys on base, stuff like that. We've done a pretty good job."
The four have gotten help this postseason from journeyman Yusmeiro Petit, whose nine shutout innings of two-hit relief were big reasons for San Francisco's wins in Game 2 of the division series against Washington and Game 4 of the NLCS against St. Louis.
Petit has been let go four times in his career, including briefly last season by the Giants, making him a perfect fit in a bullpen of mostly castoffs.
Of the seven relievers who have pitched this postseason, only Affeldt hasn't been released, waived or designated for assignment in his career. Casilla was signed to a minor league deal before the 2010 season after being let go by Oakland. Lopez was designated for assignment four times in his career before being acquired in a deadline deal with Pittsburgh in 2010.
Romo is a former 28th round pick who was designated for assignment by San Francisco in 2008 before earning a regular role in the majors.
Now they are all proven major leaguers and postseason stars that the Giants would never think of letting go.
"They thrive on being out there in a tight game, in a late situation," Bochy said. "They certainly help me make my decisions a lot easier."
AP Baseball Writer Janie McCauley contributed to this report