The number of four-strikeout frames -- made possible when a hitter takes first base after a third strike is dropped by the catcher plus either first is vacant or there are two outs -- has grown exponentially in the 21st century. While there were no such achievements by a pitcher in nearly four decades from 1917-55, there were four in 2017, six in 2016 and five more in 2021.

In September 2012, there were three 4-K innings in two days, include a pair on Sept. 26. And in 2015, Dodgers pitchers accomplished the feat on consecutive days.

"This time I didn't even notice," Zack Greinke said in 2014 after his second career four-strikeout inning. "I still wasn't pitching as well as I wanted ... and I was wrapped up in ... making sure it's not a big inning."

Below is a list of every pitcher who has notched four whiffs in an inning:

? Tyler Glasnow, Rays, July 7, 2023 (Second inning) Watch >
? Chris Martin, Dodgers, Aug. 15, 2022 (Sixth inning) Watch >
? Michael Rucker, Cubs, April 30, 2022 (Fifth inning) Watch >
? Craig Stammen, Padres, Sept. 24, 2021 (Sixth inning) Watch >
? Domingo Germ¨¢n, Yankees, July 25, 2021 (Seventh inning) Watch >
? Jonathan Loaisiga, Yankees, June 25, 2021 (Seventh inning) Watch >
? Lance McCullers Jr., Astros, May 22, 2021 (First inning) Watch >
? Tyler Glasnow, Rays, April 23, 2021 (First inning) Watch >
? Luke Bard, Angels, April 22, 2019 (14th inning) Watch >
? German Marquez, Rockies, Oct. 1, 2018 (Fourth inning) Watch >
? Miguel Diaz, Padres, July 8, 2018 (11th inning) Watch >
? Ryan Dull, A's, April 17, 2018 (Eighth inning) Watch >
? Zach Duke, Twins, March 29, 2018 (Seventh inning) Watch >
? Zack Godley, D-backs, Aug. 13, 2017 (First inning) Watch >
? Mike Bolsinger, Blue Jays, July 18, 2017 (13th inning) Watch >
? Craig Kimbrel, Red Sox, May 25, 2017 (Ninth inning) Watch >
? Nate Karns, Royals, May 3, 2017 (Sixth inning) Watch >
? Jon Gray, Rockies, Sept. 17, 2016 (Second inning) Watch >
? James Paxton, Mariners, Sept. 6, 2016 (First inning) Watch >
? Jake Thompson, Phillies, Aug. 12, 2016 (Second inning) Watch >
? Ken Giles, Astros, Aug. 7, 2016 (Ninth inning) Watch >
? Julio Teheran, Braves, May 24, 2016 (Second inning) Watch >
? Tyler Duffey, Twins, May 8, 2016 (Seventh inning) Watch >
? Will Smith, Brewers, Oct. 4, 2015 (Ninth inning) Watch >
? Sergio Santos, Dodgers, May 16, 2015 (Eighth inning) Watch >
? Kenley Jansen, Dodgers, May 15, 2015 (Eighth inning) Watch >
? Oliver Perez, D-backs, Sept. 20, 2014 (Seventh inning) Watch >
? Justin Grimm, Cubs, Aug. 29, 2014 (Ninth inning) Watch >
? Zack Greinke, Dodgers, July 25, 2014 (Third inning) Watch >
? Anibal Sanchez, Tigers, Oct. 12, 2013 (First inning) Watch >
? Alex Cobb, Rays, May 10, 2013 (Third inning)
? Tony Cingrani, Reds, April 28, 2013 (Fourth inning) Watch >
? Craig Kimbrel, Braves, Sept. 26, 2012 (Ninth inning) Watch >
? Jason Berken, Cubs, Sept. 26, 2012 (Second inning) Watch >
? Zack Greinke, Angels, Sept. 25, 2012 (Fourth inning) Watch >
? Phil Hughes, Yankees, Sept. 20, 2012 (Fourth inning) Watch >
? Steve Delabar, Blue Jays, Aug. 13, 2012 (10th inning) Watch >
? Francisco Liriano, Twins, June 5, 2012 (Fourth inning) Watch >
? Ryan Cook, A's, April 27, 2012 (Eighth inning) Watch >
? Bud Norris, Astros, April 24, 2012 (Third inning) Watch >
? Yovani Gallardo, Brewers, Sept. 17, 2011 (Fifth inning) Watch >
? Jeremy Hellickson, Rays, Aug. 25, 2011 (Third inning) Watch >
? Justin Masterson, Indians, Aug. 4, 2011 (Second inning) Watch >
? A.J. Burnett, Yankees, June 24, 2011 (Sixth inning) Watch >
? Manny Parra, Brewers, June 6, 2010 (Fourth inning) Watch >
? Felix Hernandez, Mariners, June 3, 2010 (Eighth inning) Watch >
? Luke Gregerson, Padres, Oct. 4, 2009 (Seventh inning) Watch >
? Ryan Dempster, Cubs, Oct. 4, 2009 (Fifth inning) Watch >
? Scot Shields, Angels, June 21, 2008 (Eighth inning) Watch >
? Scott Baker, Twins, June 15, 2008 (Third inning) Watch >
? Brad Penny, Dodgers, Sept. 22, 2006 (Second inning) Watch >
? Jon Rauch, Nationals, April 26, 2006 (Eighth inning) Watch >
? Mike Stanton, Mets, Aug. 3, 2004 (Eighth inning) Watch >
? Brad Lidge, Astros, June 13, 2004 (Seventh inning) Watch >
? Octavio Dotel, Astros, June 11, 2003 (Eighth inning) Watch >
? Darren Dreifort, Dodgers, May 22, 2003 (Second inning) Watch >
? Kazuhiro Sasaki, Mariners, April 4, 2003 (Ninth inning) Watch >
? Kerry Wood, Cubs, Sept. 2, 2002 (Fourth inning) Watch >
? A.J. Burnett, Marlins, July 5, 2002 (First inning) Watch >
? Frankie Rodriguez, Reds, July 22, 2001 (Seventh inning) Watch >
? Erik Hiljus, A's, June 30, 2001 (Seventh inning) Watch >
? Chuck Finley, Indians, April 16, 2000 (Third inning) Watch >
? Steve Kline, Expos, Aug. 17, 1999 (Seventh inning) Watch >
? Chuck Finley, Angels, Aug. 15, 1999 (First inning)
? Tim Wakefield, Red Sox, Aug. 10, 1999 (Ninth inning) Watch >
? Jerry Spradlin, Giants, July 22, 1999 (Seventh inning) Watch >
? Chuck Finley, Angels, May 12, 1999 (Third inning)
? Archie Corbin, Marlins, April 28, 1999 (Seventh inning) Watch >
? Kirt Ojala, Marlins, Sept. 16, 1998 (Fourth inning) Watch >
? Blake Stein, A's, July 27, 1998 (Fourth inning)
? Wilson Alvarez, White Sox, July 21, 1997 (Seventh inning) Watch >
? Derek Wallace, Mets, Sept. 13, 1996 (Ninth inning) Watch >
? Kevin Appier, Royals, Sept. 3, 1996 (Fourth inning)
? Bruce Ruffin, Rockies, July 25, 1996 (Ninth inning)
? Mark Wohlers, Braves, June 7, 1995 (Ninth inning)
? Paul Shuey, Indians, May 14, 1994 (Ninth inning)
? Matt Young, Mariners, Sept. 9, 1990 (First inning) Watch >
? Tim Birstas, Reds, June 4, 1990 (Seventh inning) Watch >
? Paul Assenmacher, Braves, Aug. 22, 1989 (Fifth inning)
? Mike Scott, Astros, Sept. 3, 1986 (Fifth inning)
? Mario Soto, Reds, May 17, 1984 (Third inning)
? Charlie Hough, Rangers, July 4, 1988 (First inning) Watch >
? Bobby Witt, Rangers, Aug. 2, 1987 (Second inning) Watch >
? Mike Paxton, Indians, July 21, 1978 (Fifth inning)
? Phil Niekro, Braves, July 29, 1977 (Sixth inning)
? Bill Bonham, Cubs, July 31, 1974 (Second inning)
? Mike Cuellar, Orioles, May 29, 1970 (Fourth inning)
? Bob Gibson, Cardinals, June 7, 1966 (Fourth inning)
? Don Drysdale, Dodgers, April 17, 1965 (Second inning)
? Lee Strange, Indians, Sept. 2, 1964 (Seventh inning)
? Pete Richert, Dodgers, April 12, 1962 (Third inning)
? Ryne Duren, Angels, May 18, 1961 (Seventh inning)
? Joe Nuxhall, Reds, Aug. 11, 1959 (Sixth inning)
? Jim Davis, Cubs, May 27, 1956 (Sixth inning)
? Guy Morton, Indians, June 11, 1916 (Sixth inning)
? Walter Johnson, Senators, April 15, 1911 (Fifth inning)
? Orval Overall, Cubs, Oct. 14, 1908 (First inning)
? Hooks Wiltse, Giants, May 15, 1906 (Fifth inning)
? Ed Crane, Giants, Oct. 4, 1888 (Fifth inning)