פירוש על עבודה זרה 11:1

If one holds that by definition a “trefa” cannot give birth, then it makes sense to exclude it from the phrase, “to keep seed alive.” But what about those who hold that a “trefa” can give birth. We would then need the earlier verse to exclude the trefa and we would have no verse to exclude the animal missing a limb.
The Talmud finds a new way of excluding the trefa—from the word “with you.” The animals that Noah sacrifices must be like Noah—able to bear offspring and not trefot.

The Talmud tries to prove that Noah was not a trefa by citing various adjectives used to describe him. But when this fails, they say simply that Noah could not have been a trefa because God would not have said “like you” if Noah himself was a trefa.