Knotts tried to negotiate his job back.
In an effort to save the gig, Knott’s offered to come back to the show with one caveat. He wanted an ownership stake in the production. Often, in modern times, powerful actors will become producers for shows to they can earn better residuals. In the case of Mayberry, only Griffith and his manager had this privilege. They turned Knotts’ offer down. He did, however, make some guest appearances.