The decision comes after a committee meeting on Tuesday where it was decided that the trio would be suspended pending hearings after failing drug tests in January.
Silva tested positive for Drostanolone and Androstane in an out-of-competition test on January 9 and for Drostanolone again on January 31. Lombard too was found to have steroids in his system, returning a positive test for desoxymethyltestosterone after a January 3 fight.
Diaz tested positive for marijuana metabolites after his January 31 bout with Silva, the third time he has done so in Nevada.
Dates for the hearings are expected to be announced in the coming days.