Tafsiran Imamat 27:11: Rashi, Rashbam, Chizkuni & Siftei Chakhamim

ואם כל בהמה טמאה AND IF IT BE ANY בהמה טמאה — Scripture is really speaking here not of an “unclean" but of a blemished animal which ,is just on this account, unclean (i. e. unfit) for sacrificing, and Scripture is telling you that sacred animals which have no blemish cannot again become non-holy (more lit., go forth from the category of holy animals to that of non-holy animals) through redemption except if they become blemished (Temurah 32b; Sifra, Bechukotai, Section 4 1).

ואם כל בהמה, an animal already sanctified as a sacrifice which had in the meantime become ritually unclean so that it no longer qualified for the altar because it had developed a physical blemish;

ואם כל בהמה טמאה, “he places a ritually impure animal before the priest (as a sacrifice) Rashi explains that this cannot be understood literally, as it is too obvious. He therefore understands the word טמאה here as referring to a blemished animal, the owner not knowing if that blemish was serious enough to disqualify said animal. The Torah teaches that such a decision must be left to the officiating priest. If it is a temporary blemish, said animal is fit as a sacrifice as soon as its blemish has disappeared.