"Two of the premier curveballs in all of baseball," said Dodgers catcher A.J. Ellis.
He would know. Ellis has handled Kershaw's usually-killer curve all season, and is 0-for-5 in at-bats against Wainwright.
"I know with Clayton's, it's such a difference-maker for him, his ability to change speeds," Ellis said. "It's hard for hitters to cover velocities from 95 [mph] all the way down to 72. When he's able to have that thing going effectively, it's tough for hitters to sit on certain speeds.
"With Adam, he's just such a competitor as well. We kind of got a taste of it the other day watching [Game 5 of the NL Division Series against the Pirates] on TV, just how confident he is with his curveball. He throws it any count, any time. He's got the ability to throw it for strikes and shorten it for strikeouts.
"It's a challenge. That's why those guys are at the top of the list every year for best pitcher in the National League."
But are these the league's two best curveballs?
That question is impossible to answer, because the effectiveness of any single pitch is so tied to the rest of an arsenal. Both Kershaw and Wainwright also possess fantastic fastballs -- a 93.2 mph average velocity during the regular season for Kershaw and 91.1 mph for Wainwright, who mixes in a cutter -- among their other weapons.
The website FanGraphs.com attempts to assign a statistical value for one particular pitch with its Pitch Type Linear Weights -- one version which measures the total runs saved with a particular pitch (designated wCB in the case of a curveball), and another that quantifies the number of runs saved per 100 curveballs (wCB/C). In both measures, Kershaw and Wainwright shine. Wainwright's wCB is 17.1, second-best in baseball to the Pirates' A.J. Burnett, who, according to the measure, saved 20 runs this season by throwing curveballs. Kershaw, with an 11.6 wCB, ranks fourth overall, and he is one of only two left-handers (Washington's Gio Gonzalez is the other) in the top 10.
When standardized with the wCB/C measure, Kershaw leads the Majors with 2.71 runs saved per 100 curveballs and Wainwright ranks eighth at 1.78.
It's worth noting again that both men are also really good with their fastballs. Kershaw's 38.2 wFB is the best in baseball, and Wainwright is 15th at 13.2.
But it's the knee-buckling curves that often get noticed.
"It's something I've had since I was a kid, and I could always throw it as hard or slow as I wanted," said Wainwright, who will work opposite the Dodgers' Hyun-Jin Ryu on Monday evening.
Wainwright learned the pitch from his brother, Trey.
"It's always been my big pitch," Wainwright said.
The origins of Kershaw's curve are murkier. He cited a series of Minor League coaches for help along the way, but could not remember precisely who taught him the grip.
"It's kind of just how it came out when I started throwing it," he said.
Kershaw considers the curve an unremarkable part of his arsenal because he throws it relatively infrequently -- 12.5 percent of his regular-season pitches, though that percentage has more than doubled over the past three seasons. In his Game 2 loss to the Cardinals on Saturday, Kershaw threw 72 pitches and 12 curveballs, eight for strikes, including a misplaced one up in the strike zone that went for a David Freese double. Freese wound up scoring an unearned run, the difference in the Cards' 1-0 win.
Wainwright features his curveball much more often -- 27.3 percent of the time in his regular-season starts. In his dominating, complete-game performance against the Pirates last week, Wainwright threw as many curveballs -- 48 -- as he did fastballs. He ended the game with three consecutive curves to the Pirates' Pedro Alvarez, all below the zone, all for swinging strikes.
"The guys who have really good ones, like Wainwright, [Detroit's Justin] Verlander, those guys throw it for strikes, so when they want to bounce one, the hitter swings at it," Kershaw said. "As long as you can throw it for strikes, the hitter has to respect it. That's the most important thing.
"I'm not saying mine is [good or bad], I'm just saying it's not my most important pitch."
Said Wainwright: "He's got a really good one. I don't even know how many left-handers even throw curveballs any more. The curveball is kind of a lost art."
Kershaw's curveball gained notoriety on March 9, 2008, when he pitched his first big game, if you can consider a televised Spring Training contest against the Red Sox a "big game." Kershaw, 19 years old and less than two years removed from being the seventh pick in the 2006 First-Year Player Draft, froze Boston's Sean Casey with a 1-2 curve that, in a video clip rediscovered earlier this year after a public plea from Grantland.com's Jonah Keri, actually made legendary Dodgers play-by-play man Vin Scully chuckle on the air.
"Oh, what a curveball!" Scully beamed. "Holy mackerel. He just broke off Public Enemy No. 1. Look at this thing. It's up there, it's right there, and Casey is history."
And the rest his history.
"I haven't been asked about that for a while," Kershaw said. "I guess [Scully] had a big reaction to it, I don't know. It was my first big league anything, so I obviously remember the outing."
Cardinals manager Mike Matheny, a catcher in his playing days, was asked about his memory of great curveballs and conjured the late Darryl Kile, a teammate from 2000-02.
"It's an art that not many people have, and then to be able to have a little velocity with it, which both Adam and Clayton do have, makes it for a tough assignment," Matheny said. "It's fun to catch, I know that."