The San Francisco Giants' World Series Secret Weapon Is a Low-Usage Long Reliever

Here we are yet again. The San Francisco Giants are back in the World Series because that's just what they do in even-numbered years. Was there ever a doubt?

This time, the Giants had a secret weapon in their trip to baseball's biggest stage. It wasn't one of the sport's best catchers in Buster Posey. It wasn't the storybook guy who won it with a walk-off in Travis Ishikawa. Nor was it Pablo Sandoval, who goes unconscious at the dish every postseason.

Instead, it was a long-reliever who was only used once in both the NLDS and NLCS: Yusmeiro Petit. While he may not be as valuable as those other guys, the dude played a major role in getting the Giants where they are, and he'll need to do so again against the Royals if they want to win it all.

Two Games, Two Cold-Blooded Performances

Yeah, it's hard to call a guy a secret weapon when he only pitches in relief in two of 10 games. But when you look at the situations the Giants have thrust Petit, his worth becomes immediately evident.

When Petit entered Game 2 against the Nationals, he hadn't pitched in relief since August 23rd. Bruce Bochy asked him to enter a tied playoff game in the 11th inning. Petit proceeded to hurl six shutout innings while allowing just one hit and striking out seven.

Obviously, the biggest thing about this performance was the zero in the run column. But the six innings was almost as crucial. At that point, the Giants had already burned five guys from their pen. Not only were they running low on arms specifically for that game, but they had also used five guys just one day prior. Petit came in, saved the pen, and kept on giving the Giants' offense chances to knock one home. Eventually they did to take a 2-0 lead in the series.

Think for a second how much different that series is if the Nationals win the game to tie it at 1-1 heading into Game 3. While events may not have transpired exactly the same, the Nationals did win. They would have had a 2-1 series lead and been one win away from the NLCS. There are too many hypotheticals to seriously consider that, but the point stands: Petit's performance in Game 2 was stupidly important to the flow of that series. Then he went out and did it again in the NLCS.

Game 4. The opponent had finally caught on to Ryan Vogelsong's stuff. Bochy was forced to turn to the pen at the start of the fourth inning, trailing 4-3. And, of course, Petit locked that puppy down.

This time, Petit threw three shutout frames, allowing just one hit again and striking out four. He provided the bridge from the short start to the back end of the bullpen while the Giants took the lead offensively. Effective middle-relief work is not the world's most abundant resource; the Giants have it in Petit. And it's very possible they'll be in need of his services again in the near future.

Petit's Value Against Kansas City

Moving Petit back to the bullpen was a pretty easy call for Bochy and the right one. In 68 innings as a starter, Petit had a 5.03 ERA while opponents hit .251/.284/.462 off of him with a .319 wOBA. In 49.0 relief innings, his ERA deflated to 1.84 with opponents being handcuffed to a line of .177/.226/.246 with a .210 wOBA. That's a no-brainer.

But plugging Petit in the bullpen also gives that unit something they completely lack without him. Petit strikes dudes out.

In his work as a reliever, Petit averaged 10.84 strikeouts per nine innings. Their other relievers averaged 6.98 strikeouts per nine. Only one other National League team was below 7.97, and that was the Rockies. The only team in the entirety of the majors lower than their mark minus Petit was the Twins, and they find the strikeout to be a repulsive proposition.

Why does this matter outside of the general value of a good ol'-fashioned strikeout? The Royals have more difficulty hitting power pitchers than finesse pitchers. Against pitchers that Baseball Reference defines as "finesse" (pitchers in the bottom third in the league in strikeouts plus walks), the Royals hit .275/.323/.394 this year. Against power pitchers (those in the top third in strikeouts plus walks), that falls to .256/.319/.372. Petit qualifies as a power guy. The others... not so much.

In addition to that, we could easily see another situation like Game 4 of the NLCS. As I mentioned in my NLCS Preview, the Giants' older starters struggle once the fifth and sixth innings roll around. With how low-scoring these games figure to be, you can't simply leave them out there to sacrifice a run or two. You have to bring Petit in and let him do his thang.

This isn't something Petit can do everyday, obviously. But if he is able to have two performances of three-plus innings of effective relief, that's enough to make an astronomic difference in a series, as the Giants showed the first two rounds. When you're facing a bullpen as filthalicious as the Royals, you need all of the help you can get.