EUGENE, OR - JULY 05: Allen Johnson pulls up in the men's 110 meter hurdle heats during day seven of the U...

Allen Johnson tripped and fell at the Athens Games

Allen Johnson of the United States is seen after he fell during the men's 110-meter hurdles...

Allen Johnson of the United States competes in the men's 110-meter hurdles

Allen Johnson, front, won the men's 110-meter hurdles at the Athletissima athletics meet in Lausanne, Switzerland...

...Oklahoma 13 February 2008: Iowa State forward Wesley Johnson (4) during the University of Oklahoma Sooners 76...to his team during the first half at Allen Fieldhouse. Mandatory Credit: Douglas Jones-US PRESSWIRE

Detroit Lions wide receiver Calvin Johnson makes a catch during the first day of minicamp Tuesday, June 23, 2009, in Allen Park, Mich. (AP Photo/Paul Sancya

23 Jan 2001: Larry Johnson #2 of the New York Knicks dribbles the ball as he is guarded by Ray Allen #34 of the Milwaukee Bucks at the Bradley Center...

Detroit Lions receiver Calvin Johnson (81) and teammates stretch during drills at an NFL football mini-camp at the team's training facility in Allen Park, Mich., Friday, April 17, 2009

...2009; West Lafayette, IN, USA; Purdue Boilermakers forward (25) JaJuan Johnson takes a shot in the lane against Michigan State Spartans guard (3) Chris Allen at Mackey Arena. Purdue defeated Michigan State 72-54. Mandatory...

...2009; West Lafayette, IN, USA; Purdue Boilermakers forward (25) JaJuan Johnson takes a shot in the lane against Michigan State Spartans guard (3) Chris Allen at Mackey Arena. Purdue defeated Michigan State 72-54

ATLANTA - DECEMBER 17: Ray Allen #20 of the Boston Celtics takes a shot against Joe Johnson #2 of the Atlanta Hawks at Philips Arena on December 17...

...31 of the Milwaukee Bucks blocked by Amir Johnson #25 of the Detroit Pistons in a preseason...Mandatory Copyright Notice: Copyright 2008 NBAE (Photo by Allen Einstein/NBAE via Getty Images

...Los Angeles, CA, USA; Southern California Trojans tailback Allen Bradford (21) at scrimmage at the Los Angeles...Los Angeles, CA. 3-April 19, 2008: Stafon Johnson (13) TB during a college football spring scrimmage...

Detroit Lions wide receiver Calvin Johnson is shown during football training camp in Allen Park, Mich., Thursday, July 24, 2008