Bearing in mind that the Torah (in Parshas Tzav) has already informed us that the Asham must be slaughtered on the north side of the Azarah, why does the Torah see fit to write "v'Shachat Es ha'Keves bi'Mkom Asher Yishchat Es ha'Chatas"?
Rashi: Because, since the Asham Metzora differs from other Ashamos in that it needs to be placed by the Sha'ar Nikanor, 1 we might otherwise have thought that it is slaughtered there, too.
See Sifsei Chachamim.
Why does it say "ka'Chatas ha'Asham Hu la'Kohen"?
Rashi: To teach us that regarding all Avodos that require a Kohen, this Asham is like a Chatas. If not for this verse, we might have thought that, since blood is placed on the ear, thumb and big toe, it is not put on the Mizbe'ach.
QUESTIONS ON RASHI
Rashi writes that it says "bi'Mkom Asher Yishchat
Zevachim 49b: Since it did not suffices to say 'where the Chatas is slaughtered', this teaches that something learned from a Hekesh (Chatas was learned from Olah) cannot return to teach through a Hekesh. 1
I do not know why Moshav Zekenim left this difficult. (PF)
Rashi writes that Asham Metzora left the Klal of Ashamos
Riva: Something that left a Klal teaches about the Klal only when it is similar to the Klal, like I said above (refer to Shemos 12:15:153:2).