The big mystery in Thursday night’s Game 2 of the World Series is what the Giants might get from the struggling Madison Bumgarner. Bumgarner posted strong overall numbers this year, but he seemed to wear down. Now the Giants say they’ve worked on a mechanical tweak and he should be more effective. It’s certainly intriguing, although one recalls that the Tigers said they worked on a mechanical tweak with Jose Valverde, and then Valverde did what he did in Game 1. Sometimes it’s nonsense. Sometimes it’s not nonsense, but it doesn’t make much of a difference. It’s a mystery, basically, again.

Less of a mystery is what the Tigers might get from Doug Fister. As Justin Verlander and Barry Zito have established, there’s always mystery when you’re talking about individual starts, but Fister is more of a known entity at the moment than Bumgarner is. Fister’s just a guy who’s quietly become one of the better right-handed starting pitchers in all of baseball. As bad as the Tigers might feel about losing a Verlander start, they have the consolation of knowing the rest of their starting rotation is really good, too.

But I’m not here to talk about the rest of the Tigers’ starters — I’m here to talk about Fister, and about one thing about him in particular. Everybody is familiar with the concept of platoon splits, as players often perform differently against lefties and righties. Fister has shown a platoon split of his own, but his is fairly unusual. Let’s begin by isolating 2012. Here’s Doug Fister in 2012 against right-handed batters, and A.J. Burnett in 2012, overall.

2012 K% BB% GB% Fister vs. R 20% 8% 61% A.J. Burnett 21% 7% 57%

Okay, great. Now here’s Doug Fister in 2012 against left-handed batters, and Joe Blanton in 2012, overall.

2012 K% BB% GB% Fister vs. L 21% 3% 44% Joe Blanton 21% 4% 45%

Don’t read too much into the difference in walk rates. Single-season splits and small samples, and all that. But that last column is somewhat eye-opening. Against righties this year, Fister was an extreme groundballer, while against lefties, Fister was neutral. And this split has held for Fister’s entire major-league career.

Since Fister broke in in 2009, 323 different pitchers have been credited with at least 100 innings against right-handed bats. Fister’s 55.2-percent groundball rate ranks 33rd out of the pack, around Scott Diamond and Santiago Casilla. Meanwhile, since 2009, 233 different pitchers have been credited with at least 100 innings against left-handed bats. Fister’s 41.6-percent groundball rate ranks 153rd out of the pack, around Jair Jurrjens and Matt Garza. Fister has become more of a groundball pitcher over time, but the lefty/righty split hasn’t shrunk. Righties keep the infield busy, while lefties give the outfielders something to do.

Oftentimes, what you’ll see is that a right-handed pitcher will generate fewer strikeouts and more walks against left-handed batters, and somewhat offset that by generating a higher rate of grounders. For his career, Fister’s walk rates are identical, his strikeout rate is higher against lefties, and his groundball rate is far higher against righties. Fister presumably isn’t the only pitcher like this, but his split strikes me as an uncommon one.

It’s mostly because of Fister’s fastballs. Lefties see more changeups and fewer two-seamers than righties do, but the curve and change are still groundball pitches. Let’s group Fister’s four-seamer, two-seamer, and cutter together. Since 2009, those pitches have generated 56-percent grounders against righties and 37-percent grounders against lefties. Just in 2012, the split was 63 percent and 41 percent. This is the key to the whole thing.

And unsurprisingly, Fister’s usage patterns are different. Fister likes to wear righties out with his fastballs inside, though sometimes he’ll put a cutter over the outer half. But Fister likes to stay away from lefties with his fastballs, though he’ll come in with cutters and two-seamers from time to time. The location patterns probably have something to do with the split, and naturally the pitch movements probably have something to do with the split. Against Fister, righties get jammed. Against lefties, the ball moves toward the end of the bat.

Here are two .gifs to prove beyond a reasonable doubt that Fister has generated at least one grounder from a righty and at least one fly ball from a lefty.

Doug Fister is Doug Fister, but against righties, he is a different pitcher from who he is against lefties. Overall, against Fister, righties have posted a .093 isolated slugging, while lefties have posted a .151 isolated slugging. Lefties have hit more than twice as many home runs in just 27 percent more plate appearances. Anybody could conceivably drill an extra-base hit against Doug Fister, but lefties stand a better chance.

The Giants’ Game 2 lineup will look identical to their Game 1 lineup, with an irrelevant pitcher substitution. Marco Scutaro, Buster Posey, Hunter Pence, and Madison Bumgarner will bat from the right side, leaving Angel Pagan, Pablo Sandoval, Gregor Blanco, Brandon Belt, and Brandon Crawford to bat from the left side. One angle is that Sandoval has a chance to continue his home-run barrage. Another angle is that Blanco or Pagan could find three bases in the outfield vicinity of Delmon Young. Still another angle is that tonight might not be the night that Posey re-discovers his power swing. There are a lot of ways one could go with this. It’s just one game between two teams with two lineups and two starters. But one of those starters is kind of like two starters on his own, even if he doesn’t look it to the eye.