Q. If one recited Shema before davening, may he skip it during davening (and just say the brachos) in order to have tefilla b'tzibbur?
A similar question, If one davens ma'ariv after plag, can he shorten or rapidly read the Shema in order to have tefilla b'tzibbur, since he has to repeat Shema at night?
A. Horav Shlomo Miller's Shlit'a opinion is that reciting the shema between the brochos of shacharis or ma'ariv is an essential part of the structure of these tefilos, and cannot be omitted, although in your case, it could in need be read more speedily than usual. A person who came late for ma'ariv, may first daven the amida together with the tzibur, and afterwards recite the brachos and the shema properly. (Shulchan Aruch O.H. 236: 3)
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a