Tosefta for Zevachim 169:13
ולמאן דאמר אין הפשט ונתוח בראש המזבח מאי איכא למימר הכא במאי עסקינן כגון שהיתה לו שעת הכושר ונפסלה ורבי אלעזר ברבי שמעון היא דאמר כיון שנזרק הדם והורצה בשר שעה אחת יפשיטנה ועורה לכהנים
that flaying and dismembering can be done on top of the altar. Then on the view that flaying and dismembering cannot be done on top of the altar, what can be said? - The case we discuss here is, e.g. , where it had a period of fitness and then became disqualified,<span class="x" onmousemove="('comment',' It refers indeed to a fit animal which ascended alive, but after it was slaughtered on top of the altar and its blood was sprinkled, it became disqualified; therefore it must be flayed and dismembered on top of the altar, for if it is taken down it may not be taken up again, since it was disqualified. And as to the objection that an unfit animal cannot be flayed, the answer is that it had a period when it was fit for flaying before it became disqualified.');"><sup>12</sup></span>