Major League Baseball had seen pitchers submit almost 7,000 qualified seasons from the beginning of the Live Ball Era in 1920 through the end of 2016. Out of those thousands of resumes, only two pitchers had struck out as many as 35 percent of the batters they had faced: Pedro Martinez in 1999 (37.5 percent) and Randy Johnson in 2001 (36.7 percent).
Both of those were Cy Young Award-winning seasons that still resonate nearly two decades later. But with three weeks left in this season, those two Hall of Famers may soon have company.
In >7,000 qualified SP seasons from 1920-2016, only 2 posted a 35% strikeout rate (Pedro '99, Randy '01).
Sale, Scherzer and Kluber are blowing away more than one out of every three batters that they face. It's a breathtaking pace to watch, and a relentless, brutal one for whoever has to face these three aces.
Let's go down memory lane for proper context. Martinez's 1999 Triple Crown campaign (23-4, 2.07 ERA, 313 strikeouts) for the Red Sox is considered by some as the greatest individual pitching season in history, rivaled perhaps by his 2000 follow-up that was equally as incredible. Martinez also struck out five of the first six batters in the 1999 All-Star Game, and he later punched out 17 Yankees in the Bronx in a memorable one-hitter.
Johnson's intimidating fastball-slider combo reached full maturation in 2001, when the lefty struck out a career-high 372 batters that remains the third-highest single-season total by any Live Ball Era pitcher. Johnson struck out 20 Reds in nine innings in early May that year, recorded an immaculate inning against the Pirates in August, and he compiled one of the best postseason performances of all-time that October.
This year's trio may not have put together performances as incredible as those, but they've been consistent. Sale tied the record he previously held with Martinez when he posted double-digit strikeout totals in eight straight starts from April 10-May 19, and Sale later joined Johnson, Martinez and Nolan Ryan as the only pitchers to record 200 strikeouts in their first 20 starts of a season. Sale is also on pace to join Johnson as the second left-handed pitcher in the American League to strike out at least 300 batters since the designated hitter was introduced in 1973.
"It's cool. I definitely appreciate it," Sale told MLB.com when he joined that exclusive 200-strikeout club. "I'm not the biggest fan of looking into stuff like that. Those things are for the offseason or to one day tell my grandkids or something like that."
While Scherzer's health has become a concern down the stretch, the National League Cy Young Award favorite still stands on the doorstep of his fourth consecutive season with at least 250 strikeouts -- a feat no pitcher has accomplished since Martinez from 1997-2000. With just one more 10-K performance, Scherzer would also join Johnson, Martinez, Dwight Gooden, Sandy Koufax and Curt Schilling as the only NL pitchers to record at least 15 double-digit-strikeout games in a single season.
Sale and Scherzer have grabbed headlines from the very beginning, but Kluber -- ever the late bloomer -- is up to his old tricks again. On the morning of June 1, Kluber owned a 5.06 ERA and a strikeout rate of just 25.9 percent as he prepared for his return from the disabled list. Then he struck out 10 A's batters that afternoon, and he hasn't looked back. No starting pitcher has posted a lower ERA (1.89) or struck out a higher rate of batters (37.7 percent) than Kluber since that day.
"His routines are impeccable,'' Indians manager Terry Francona said to MLB.com of Kluber's now-trademark late-season surge. "His tank doesn't look like it's half-empty."
Now that Sale, Scherzer and Kluber are hovering around the historic 35 percent threshold, can they catch Martinez and Johnson for the all-time single-season strikeout rate? It would take some incredible -- but certainly not unprecedented -- closing efforts. Assuming each pitcher will make four more starts and face an average of 26 batters each time, Sale is the closest. The Red Sox star needs to average 11 strikeouts per start to pass Johnson's 36.7 percent rate from 2001, and 13 per game to pass Martinez's all-time mark. Kluber and Scherzer would each need to average and 13 per outing to reach Johnson, and 14 punchouts per start to surpass Martinez.
Should they get there or not, the simple counterargument is that batters are striking out more this year than they ever have before. That's true, but batters are also walking a bunch, too, and this trio is also on track to post three of the best seasons in terms of strikeout-minus-walk percentage. As Cy Young Award debates begin to reach fever pitch, it's time to appreciate the incredible artistry Sale, Scherzer and Kluber are showing on the mound.
Matt Kelly is a reporter for MLB.com based in New York. Follow him on Twitter at @mattkellyMLB. This story was not subject to the approval of Major League Baseball or its clubs.