Floyd Mayweather tells TMZ Sports ... Logan's little bro is "probably" his next opponent, after he takes on Logan on Sunday.
... and why?? MONEY! MONEY! MONEY!
Check this out ... 44-year-old Floyd says he expects to make between $50 and $100 MILLION for the 8 round exhibition against Logan and believes he can pull similar figures against Jake.
In fact, Floyd tells us he's already raked in somewhere around $30 million for the Logan fight -- and that's in guaranteed cash before he even throws a punch.