Interestingly enough, in 1970, Kermit the Frog was intended to be dropped from Sesame Street, only to be shown in the second season in existing segments. "When the new season starts November 9, expect changes. There will be no more know-it-all frog, since Kermit, the one Muppet who is not exclusive to Sesame Street, is opting out to do commercials" (Look, Sept. 22, 1970). Time Magazine reported with slightly more detail: "Kermit the Frog is being canned for commercialism. When Sesame Street was just a glint in Joan Ganz Cooney's eye, Kermit taped a special in Canada. When it was given a network airing, the frog was compromised. Or so Henson decided. .... He is being phased out of the show. He will be replaced by such Muppets as Herbert Birdsfoot and Sherlock Hemlock" (Time, November 23, 1970).
However, Kermit made one sketch during the second season on a lecture about "between", and ultimately, of course, that did not turn out to be the case, as Kermit reappeared as a Sesame Street character in the third season (1971).