Why doesnt tos. ask a more obvious question that the gemara comes out lemaskana that if the tzitz will not be meratza even if it only mederabanaan (Tos Divrei hamaschil asaum) then the kohanim can eat the bosor then why does the gemara in yevomos say that since the tzitz is not meratza then the kohanim can't eat it
shmuely kass, Lakewood NJ USA
The Gemara here is talking about where the Eimurim were Nitme'u. The Haktaras Eimurim is not a Matir for the Achilas Basar, as we see that if they were lost one may still eat the Basar without Haktarah. However, one may not eat the Basar before the Haktarah as long as they are here. Therefore, we say that it is as if they are not here and the Kohanim can eat the Basar.
In Yevamos, the Gemara is speaking about Zerikah. Zerikah is a Matir of the Basar; if the Zerikah is Pasul, the Basar is Asur b'Achilah and there is Me'ilah. There, we need Ritzuy ha'Tzitz in order to be Machshir the Zerikah in order to be Matir the Basar.
D. Zupnik