The WBC welterweight champion and pound-for-pound king takes on WBA champion Alvarez in two weeks.
He reacted angrily to claims that the Mexican has been knocking out his sparring partners.
"I couldn't care less what the rumour is about Canelo's [Alvarez] camp," Mayweather told RingTV.
"I'm not a f***ing sparring partner, I'm Floyd Mayweather and I can f***ing fight."
Both fighters are unbeaten going into the September 14 bout.