Michael Vick has been suspended indefinitely without pay by the NFL after pleading guilty to involvement in a dog fighting operation.
Vick has admitted helping to bankroll a dog-fighting ring
The Atlanta Falcons star, one of US sport's biggest names, was heavily criticised by NFL chief Roger Goodell.
The commissioner described Vick's conduct as "not only illegal but also cruel and reprehensible".
Vick faces a maximum $250,000 fine and five years in jail, although his plea is likely to mean a shorter term.
Goodell said: "Your actions in funding the betting and your association with illegal gambling both violate the terms of your NFL player contract.
We hope that Michael will use this time... to take positive steps to improve his personal life
Falcons owner Arthur Blank backs Vick's suspension
"They expose you to corrupting influences in derogation of one of the most fundamental responsibilities of an NFL player."
Falcons owner Arthur Blank issued a statement saying: "Michael's admissions describe actions that are incomprehensible and unacceptable for a member of the NFL and the Atlanta Falcons.
"We respect and support the Commissioner's decision to place him on an indefinite suspension.
"As with other actions he has taken this year, the Commissioner is making a strong statement that conduct which tarnishes the good reputation of the NFL will not be tolerated.
"We hope that Michael will use this time, not only to further address his legal matters, but to take positive steps to improve his personal life."
Vick has admitted bankrolling a dog-fighting ring and helping to kill up to eight dogs after they lost fights.
The quarterback signed a 10-year, $130m (£65m) contract with the Falcons in 2004, and also earns millions more in endorsements.
But he was banned from training camp by Atlanta earlier this summer as the dog fighting case came to light, and now faces an uncertain future in the game.