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 Germán, 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) Watch >
• 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)