Simmons is still awaiting extradition to Arizona on other outstanding drug charges.
Simmons was originally released on bond on the Miami drug charges but was jailed two weeks ago after he was arrested on the outstanding warrant from Arizona. He was denied bond at that time and has been in jail since.
Simmons' attorney said that rather than remain jailed until his scheduled trial in October, he decided to plead guilty. He was sentenced to time served.
"He got shafted on this one," said his attorney Bradford Cohen, referring to the "weak and flawed" evidence in the Miami case.
In Arizona, Simmons faces charges of marijuana possession and possession of drug paraphernalia. He also faces animal cruelty charges after authorities found dog carcasses and malnourished dogs on his Phoenix property.