TT #296 · Parshas Tazria · Aliyah 7 · Passuk 56
English: If the priest examines it and the lesion has faded after it was washed, he shall tear it out of the garment, leather, warp or woof.
Chabad.org — Chumash, English translation + Rashi for Vayikra 13:56
Torah Temimah cites Sifra (Toras Kohanim) for requiring the affected portion to be removed rather than merely slit or left attached.
Sifra — Vayikra 13, Midrash Sefer
English: Might one tear a small hole and thereby fulfill the requirement? The word “it” teaches otherwise; might one tear it but leave it in place? The phrase “from the garment” requires removing the affected piece.
Textual derivation
The affected section must be removed from the garment completely. A small tear is insufficient, and even tearing the whole affected section without taking it away does not satisfy the command.