Floyd Mayweather Begs To Be Released After 12 Days In Jail

The joint is taking a toll on boxing great Floyd Mayweather, and he is crying the blues about his incarceration is not allowing him to train and eat right which will demolish his career...

Floyd is currently serving time for domestic abuse, against his baby mother last year..

Mayweather made the statements in new legal papers ... in which he begs the judge to release him from the Clark County Detention Center in Nevada and let him serve the remaining time in his 3-month sentence on house arrest.

In the docs, Mayweather says he spends 23 hours-per-day locked in isolation for his own safety. But he claims the imprisonment is taking a "cruel and inhuman" toll on his rippling physique because he can't train at a world class level while serving his time.

Mayweather claims his doctor is concerned about his "dehydrated appearance, his lack of muscle tone and his dry mucus membranes."

Floyd says his doctor also "expressed deep concern for [Floyd's] health and explained that any lengthy period of time with an inappropriate diet, coupled with lack of regular exercise, will most likely lead to irreversible damage to Mr. Mayweather's physique."

Floyd's doctor also told the court he's concerned about Floyd's diet ... because he used to eat 3,000 to 4,000 calories per day ... and now, the doc believes FM is eating less than 800.

In the papers, 35-year-old Floyd estimates he only has 2 years of boxing left in his career ... so every day counts.

UPDATE: Floyd's request for release was DENIED by the judge!

Talk about a cry baby! He can whoop his baby mother's a$$, but can't take a couple of months in jail! Sounds PERSONAL...