Are the Giants Too Lefty-Heavy?

In the top of the fifth of what became an extra-inning win last Friday night, the Giants were ahead a run. Barry Zito was 100 pitches in and had been lucky to escape the top of the fifth with one run after he allowed two singles, a walk and a home run. Manager Bruce Bochy therefore sent the team’s best available right-handed hitter to the plate to pinch hit for his starter.

Matt Cain.

In the top of the ninth inning of what became a walk-off loss last Saturday night, the Giants needed any run they could get. Once Terry Collins put the Mets’ best left-hander on the mound, Tim Byrdak, lefty Brandon Crawford didn’t perhaps provide the Giants with their best chance. Bruce Bochy sent one of his two remaining right-handed hitters to the plate — backup catcher Hector Sanchez. The Giants ended up tying the game, and needed a middle infielder with Crawford out. With Manny Burriss already in the game, Bruce Bochy moved Burriss to shortstop and put his best remaining option at second base.

Aubrey Huff.

Both of these iconic moments, coming on consecutive days, made for some mirth on the internet. Much of it was unearned, really — Ryan Theriot was sick with the flu and couldn’t make the trip to New York. As a right-handed middle infielder, he would have solved both situations.

On the other hand, both situations were brought on, at least partially, by the left-handers facing the Giants on the mound. In the search for a right-handed bat to face those lefties, Bochy had to turn to Cain (.147 career wOBA) and Sanchez (.277 career wOBA, .282 rest-of-season projected ZiPs wOBA) in important moments. The Giants have the second-worst wRC+ against left-handers in the National League (56, the Pirates have a 55). The titular question seems fair: are the Giants too lefty-heavy?

Last year, no team had fewer at-bats that featured their right-handed hitter against a left-handed pitcher. The Pirates and the Giants had 545 of those situations. The Padres, at 1357, found the platoon advantage more often than any other National League team. The Giants achieved those matchups 60% less often than the league leader. This year, they once again find themselves behind the mean, even if the short sample so far means that the schedule may not have evened out yet.

But how does this jive with the Giants’ actual roster construction? Are there actually more lefties on the team that are skewing the results, and is the bench full of southpaws? Unclear:

The Giants are no more lefty-heavy than your average National League team.

And yet, there’s still the fact of those missing righty-vs-lefty matchups. How does that happen? Perhaps it has something to do with exactly how the roster is constructed. One thing that the Pirates and Giants had in common last year was that they featured two lefty first basemen (Lyle Overbay and Garrett Jones). The Giants are currently sporting Brandon Belt and Aubrey Huff and have a somewhat random plan for their use. With righty Brett Pill in the fold, they’re using three men to fill the job of a two-man platoon role.

Another way of saying it: The Giants have some righties on the bench, but they come in the form of players at premium defensive positions: Hector Sanchez, Manny Burriss and Ryan Theriot. There isn’t a league-average bat in the group. Which is how you end up with Brandon Belt pinch-hitting against Antonio Bastardo — if he’s your best bat on the bench, the platoon advantage goes out the window.

The team probably could have used a right-handed bat-first piece on the bench that day — maybe in Gregor Blanco’s spot — but they didn’t have him, and possibly because there are two lefty first basemen on this team. Which brings us back to the Huff/Belt quandary.

The Giants aren’t too lefty-heavy. That doesn’t mean that their roster is perfectly platoon-ready around the edges.