All football cornerbacks get beaten for touchdowns, and those embarrassing plays make the game’s highlights. ‘Cornerbacks need short memories” is a popular football adage. A cornerback needs to forget about the play where he was beaten and go on to the next play.
 
“What a cornerback truly needs, Lem Barney once stated, is ‘a short memory’” was cited in print in 1976. Lem Barney (who made the pro football Hall of Fame) was a cornerback for the Detroit Lions from 1967 to 1977, but it’s not known when he originally made the remark.
 
   
Google Books
Joe Namath, and the Other Guys
By Rick Telander
New York, NY: Holt, Rinehart and Winston
1976
Pg. 25:
What a cornerback truly needs, Lem Barney once stated, is “a short memory.”
     
Sports Illustrated
Originally Posted: December 18, 1978
One Moment In Three Careers For the author, the photograph of him failing as a pass defender in the 1971 East-West Game summoned up a painful memory. For Mel Gray, who caught the ball, and Dan Pastorini, who threw it, the recollection is elating
BY RICK TELANDER
(...)
It has been said that there is nothing as humiliating, as absolute, in all of sport as getting beaten on a long one. I tend to agree. Lem Barney once said that the first thing a good defensive back must have is a short memory.
 
17 January 1983, Dallas (TX) Morning News, “Cowboys: Thurman given a temporary reprieve” by Barry Horn, pg. 8B, col. 3:
“You have to be prepared to fail and be able to bounce back,” he said. “I know it has been said before, but a cornerback has to have a short memory.”
(Dallas Cowboys defensive back Dennis Thurman.—ed.)
 
Google Books
Quarterbacks, Nickelbacks & Other Loose Change:
A Fan’s Guide to the Changing Game of Pro Football
By Kevin Lamb
Chicago, IL: Contemporary Books
1984
Pg. 154:
The position required short memories and calloused psyches because, since the forward pass became popular, only one thing has ever been certain about playing cornerback. Every cornerback knows sometime soon, maybe on the next play, another receiver will chew him up and spit him out for six points.
 
Google News Archive
13 January 1996, Wilmington (NC) Morning Star, “Burden on the back of Hornets star” (Knight-Ridder-Tribune News service), pg. 2C, col. 4:
“They talk about cornerbacks need short memories when they get burned in a game. The same goes here. You don’t let it carry over.”
(Charlotte Hornets basketball player Larry Johnson.—ed.)
   
Google News Archive
5 August 1998, Pittsburgh (PA) Post-Gazette, “Steelers’ Johnson still going strong,” pg. D-2, col. 5:
Kickers, like cornerbacks, need to have short memories.
 
Google Books
Coaching Football Successfully
By Allan Trimble
Champaign, IL: Human Kinetics
2005
Pg. 145:
Cornerbacks must have short memories. They play the toughest position on the field and must cover the fastest players on the field. Look for athleticism and confidence.
 
Google News Archive
1 December 2006, Pittsburgh (PA) Post-Gazette, “Steelers Notebook: Ravens defeat a blur for Taylor” by Gerry Dulac, pg. D-6, col. 5:
Cornerbacks are often told they should have short memories. Ike Taylor, though, took it to the extreme.
 
Twitter
Nate Ulrich
‏@NateUlrichABJ
In reference to Eric Wright’s need to bounce back, #Browns coach Eric Mangini said, “Cornerbacks need to have short memories.” #NFL
1:47 PM - 27 Sep 2010
 
ESPN.com
December, 31, 2014 8:00 AM ET
Ravens’ pride on line in rematch with Big Ben
By Jamison Hensley | ESPN.com
OWINGS MILLS, Md.—There’s an old adage in the NFL that cornerbacks need short memories because they can never be perfect. But, heading into Saturday’s playoff game in Pittsburgh, Baltimore Ravens cornerback Lardarius Webb hopes every player in the secondary remembers what happened the last time they stepped on to Heinz Field.