Welcome to baseball's golden age of strikeouts. We can only imagine the numbers Nolan Ryan, Sandy Koufax, Tom Seaver and Bob Feller would be racking up today. Gone are the days when hitters choked up and tried somehow to keep it in play to avoid the embarrassment of a K. They're swinging from the heels now from first pitch to last.
Fourteen of the 15 highest strikeout seasons by hitters have been turned in by active players. This must have the all-time king of Ks, Reggie Jackson, smiling. Mr. October took the shame out of punchouts, peaking at 171 whiffs in 1968.
The Brewers' Mark Reynolds has three of the top six individual strikeout seasons in history, including his record 223 in 2009. Adam Dunn fell one short three years later.
Nine of the top 20 pitchers in strikeouts per nine innings (at least 1,000 career innings or 100 decisions) are active, according to Baseball-Reference.com.
The Rangers' Yu Darvish already owns one of the top 14 seasons in history -- 11.89 in 2013 -- and is at 11.35 this year. His 11.2 career number (545 1/3 innings, 64 decisions) would top the list if he qualified.
Here are MLB's top 20 career leaders in strikeouts per nine innings:
1. Randy Johnson, 10.61
The Big Unit towers above the crowd, having led the league nine times in a 10-year run from age 28 to 38. His high for a season was an all-time record 13.4 in 2001 with the World Series-champion D-backs. Johnson boasts six of the top eight seasons in history.
2. Kerry Wood, 10.32
Wood unleashed a career high 12.58 Ks per nine -- the third highest in history -- at age 21 in his 1996 rookie season with the Cubs. He led the NL again in 2003 (11.3) and was still putting away hitters (10.1 Ks per nine) at 34 in 2011, back with Chicago as a reliever.
3. Pedro Martinez, 10.04
Martinez led his league five times in seven years, from 1997, his final season with the Expos, through 2003 with the Red Sox. In 1999, in one of the greatest seasons ever produced by a pitcher, Pedro struck out a career-best 13.2 per nine innings, surpassed only by Johnson's 13.4.
4. Nolan Ryan, 9.55
The "Express" led his league a record 12 times, from age 25 with the '72 Angels to age 44 with the '91 Rangers. He predated the free-swinging era and pitched through 27 seasons. At 40 he put together his best season (11.48) in 1987 -- 12th all-time, right ahead Dwight Gooden's magical 1984 rookie year when he fanned 11.39 per nine.
5. Max Scherzer, 9.54
6. Tim Lincecum, 9.50
The active leaders are an impressive duo. Scherzer and Lincecum are each 30, and seemingly just coming into his full powers with a season for the ages.
Scherzer, who led the AL at 11.1 in 2012, is fourth in the AL at 10.2 this season. Lincecum, the NL leader for three consecutive years (2008-10) with a best of 10.5 in '08, is currently sending away 8.2 hitters per nine innings.
7. Trevor Hoffman, 9.36
Relying on a masterful changeup, Hoffman -- the top reliever on the list -- wasn't the prototypical overpowering closer but averaged double figures seven times with a high of 12.3 Ks per nine in 1997, his first season with the Padres. At age 40 he came in at 9.1.
8. Clayton Kershaw, 9.36
Kershaw's 10.8 strikeouts per nine innings is leading the NL and second in the Majors behind Darvish's 11.35. Clayton's previous best is 9.7 in 2009, his first full season as a starter.
9. Sandy Koufax, 9.28
Like Ryan, Koufax worked in a small-ball era. He led the National League in six of his final seven seasons with a high of 10.5 in 1962, matched in '57 when he was a spot starter in Brooklyn searching for control. When he found it, he was virtual perfection until his arthritic left elbow forced an early retirement following the '66 season.
10. Oliver Perez, 9.26
The shocker. Having a solid season as a D-backs reliever, Perez is 64-77, 4.44 ERA in his career. His best of 12.6 Ks per nine came last year as a Mariners reliever. He led the NL in 2004 at 11.0 as a Pirates starter.
11. Francisco Liriano, 9.11
12. Gio Gonzalez, 8.88
13. Sam McDowell, 8.86
14. Johan Santana, 8.83
15. Dan Plesac, 8.74
A run of five straight lefties. Liriano, 30, is missing bats (9.5 Ks per nine) but struggling (3-8, 3.82) after a superb 2013 season with the Pirates. He had 10.7 punch-outs per nine in 2006 as a Twins teammate of Santana, arguably the game's best pitcher in his prime. Johan led the AL three straight years (2004-06) in Ks per nine and has a high of 11.4 in '02.
"Sudden Sam" McDowell. The AL's answer to Koufax, led the league six times in a seven-year span with a high of 10.7 Ks per nine in '65. Gonzalez, at 9.5 this year with the Nationals, led the NL at 9.3 in 2012. His career best of 9.9 came with the '09 Athletics.
The second reliever on the list, Plesac reached double digits in 10 of his 18 seasons with a peak of 13.5 in 2001 for the Blue Jays.
16. Hideo Nomo, 8.7344
17. Lee Smith, 8.7324
18. Arthur Rhodes, 8.7297
Nomo was the pioneer for Darvish, Masahiro Tanaka and all the strikeout artists to come from Japan. Nomo led both leagues, as a 1995 Dodgers rookie with 11.1 Ks per nine and in 2001 with the Red Sox (10).
Smith put hitters away as a closer for eight teams across 18 seasons with a best of 12.2 Ks per nine with the '89 Red Sox. A left-handed version of Smith, Rhodes hit double digits six times with a high of 11 with the great 2001 Mariners outfit.
19. Scott Kazmir, 8.69
20. Yovani Gallardo, 8.65
Kazmir, the American League strikeout king with the '07 Rays while averaging 10.4 Ks per nine, seemingly was finished in 2011 but has rebounded with back-to-back strong seasons. After averaging 9.2 Ks per nine for the Indians last year, he's at 7.7 with 13 wins for the A's this year. Gallardo has been consistently good for the Brewers, peaking at 9.9 Ks per nine in 2009. He's at 7.0 this season.
Ten active pitchers on the verge of breaking into the top 20: Erik Bedard, 8.60; Cole Hamels, 8.55; Jake Peavy, 8.54; Felix Hernandez, 8.51; David Price, 8.40; Josh Beckett, 8.34; Justin Verlander, 8.33; A.J. Burnett, 8.29; Ubaldo Jimenez, 8.24; Jon Lester, 8.19.
Lyle Spencer is a columnist for MLB.com.