His lawyers and doctor had warned in court documents that his boxing career might be at risk because jail food and water did not meet his needs and lack of exercise space in a cramped cell threatened his health and fitness.

Mayweather, 35, received about 30 days off his 90-day jail sentence for work time and good behaviour. He did not speak as he got into a blue Bentley sedan just after midnight and drove himself away.

Promoters for Mayweather’s main rival, Philippine boxer Manny Pacquiao, plan a fight on November 10 at the MGM Grand Garden arena in Las Vegas.

Pacquiao’s opponent has not been named, but Mayweather is not believed to be on the list.

To fight in Las Vegas, Mayweather will need a new licence from the Nevada Athletic Commission. His last licence, for a May 5 bout against Miguel Cotto, was for one fight only.

If Mayweather applies, commission chairman Raymond “Skip” Avansino Jr could decide to grant approval or summon him before the panel for a public hearing.

The boxer pleaded guilty last year to reduced domestic battery charges stemming from a hair-pulling, arm-twisting attack on his former girlfriend, Josie Harris, while two of their three children watched.

The plea deal allowed him to avoid trial on felony charges that could have got him up to 34 years in prison.

Ms Harris and the children have since moved to the Los Angeles area.

As a high-profile inmate, Mayweather had an individual cell and was kept separate for his protection from the other 3,200 inmates in the central Las Vegas jail.