"I've heard of it," says Schimpf, who homered, doubled and drove in four runs in the Padres' 14-1 win over the Rockies on Thursday. "I don't know what the heck it is."
Nor does Schimpf have any obligation to know what the heck ISO is. It's a niche statistic, and his time is better spent preparing for opposing pitchers than worrying about numbers.
But from the outside looking in, ISO gives us the best way to understand just how remarkable Schimpf's rookie season has been.
ISO measures a hitter's extra bases per at-bat -- removing singles from the equation entirely. The goal is to measure raw power by judging a batter's ability to hit for extra bases.
Right now, Schimpf -- who has 50 hits and only 12 singles -- has posted a .367 clip. That's a number which hasn't been seen for quite some time. Take a look at the single season ISO leaderboard since 2000 (with a minimim of 250 plate appearances):
1. Barry Bonds, 2001 Giants, .536 ISO
2. Bonds, 2004 Giants, .450
3. Mark McGwire, 2000 Cardinals, .441
4. Bonds, 2002 Giants, .429
5. Sammy Sosa, 2001 Cubs, .409
6. Bonds, 2003 Giants, .408
7. Bonds, 2000 Giants, .381
8. Jim Thome, 2002 Indians, .373
9. Ryan Schimpf, 2016 Padres, .367
10. Luis Gonzalez, 2001 D-backs, .363
That's some pretty elite company -- and not the kind of company in which you'd expect to find a 5-foot-9 rookie middle infielder. But McGwire, the Padres' bench coach, isn't surprised to see Schimpf's name up there.
"When he hits it, he squares it up pretty dang good," said McGwire. "He gets really good backspin on the ball. ... These extra-base hits -- he's done it all throughout the Minor Leagues. The great part about this is that now he's shown that he can do it up here, too."
Two nights ago, Padres manager Andy Green gave an apt description of Schimpf's plate approach -- which could be the driving force behind his power numbers. In his third at-bat Tuesday night, Clay Buchholz threw Schimpf a first-pitch changeup. Schimpf powered up, then swung through it and missed.
"We have a lot of guys that see that changeup, they'll slow the bat down," Green said. "They [decelerate] to put the ball in play. He's going to fire off his A-swing, and he's going to do it over and over and over again. That gives him the ability to drive some balls out of the ballpark."
Sure enough, Rockies starter Jeff Hoffman tried to sneak a first-pitch changeup by Schimpf in the third Thursday. The slugging second baseman put his "A-swing" on the pitch and deposited it into the beach area in right-center field. Schimpf has gone deep 18 times in his first 69 games -- easily the most ever by a Padre. He's batting just .234, but he's reaching base at a .351 clip and slugging an absurd .600.
Further proof of Ryan Schimpf's outlier season. Here are all players with at least 250 plate appearances this year: pic.twitter.com/bvol1ShhpC
Essentially, the Padres are happy to take a few extra strikeouts if it means Schimpf continues to hit for extra bases at such an unprecedented pace. Schimpf says he changes his approach with two strikes, but it's certainly not a complete overhaul.
"With two strikes, I'm going to battle," Schimpf said. "But even with two strikes, I'm trying not to let off the gas. That just doesn't work for me with who I am. I'm still going to cut it loose."
Schimpf has cut it loose all season, and if he continues at his current pace, he'll finish with the highest ISO by a rookie in Major League history.
Not that he's keeping tabs.
"Like I said, I had no idea what it was," Schimpf said. "I'm just trying to drive the ball, every time. I'm not trying to place it, whatever. Wherever it's pitched, I'm just trying to fire off a swing that'll drive it."
AJ Cassavell covers the Padres for MLB.com. Follow him on Twitter @ajcassavell. This story was not subject to the approval of Major League Baseball or its clubs.