I was looking at the maharsha on the words of abaye that even a talmid chacham needs to say one passuk of rachamim, and the maharsha says its in place of tefillas arbis. its a little confusing as to why he has to say a passuk bmkom tefillas arbis did he not already daven arbis like reb yehoshua ben levi already said in the begining
Marcus Abisror, Lakewood
You are absolutely right, and many other Talmidei Chachamim have raised this point. Some go so far as to say that there is a misprint and that words should be added or changed (although I am not personally pleased with that approach).
Some want to say that Abaye's words refer to a Talmid Chacham who was Patur from Ma'ariv, but, as you noted in your question, this is not the apparent understanding of the Gemora.
In the Sefer Ishei Hash-m, by ha'Rav Aryeh She'ar Yashuv (page 233, or page 258 in Otzar ha'Chochmah), there is an interesting solution to this problem: He offers that perhaps when the Sages established the "Mitzvah" of Keri'as Shema Al ha'Mitah, they made it similar to the real Keri'as Shema. That is to say, just as Keri'as Shema is followed by Tefilah, so Keri'as Shema Al ha'Mitah is also followed by Tefilah, and therefore even a Talmid Chacham must say one Pasuk "in the place of Arvis." This is a fascinating possibility, although the only proof of such an approach seems to be the question on the Maharsha. Another question would be that it is a subject of great controversy if the saying of Shema is considered a Mitzvah or not (hence the quotation marks above).
Shimon Brodie