Whitaker deals with the following objection from the Romanists: any early church fathers who did not acknowledge the Deutero-canonical books (hereafter DC books) did so before the canon was fixed. After the canon was fixed, we do not have such liberty. Whitaker then asks this simple question: when was the canon of the Romanists fixed? The councils of Florence and Trent are modern (Whitaker, 63), and the council of Carthage was not a general council. If it is the Trullan council, Whitaker objects that “those canons are censurable in many respects, even in the opinion of the papists themselves” (63). The upshot is this: “Except this Trullan council, they have absolutely none at all. And this Trullan does not precisely affirm these books to be canonical, but only confirms the council of Carthage; which is of no consequence, since it also confirms the council of Laodicea, and the papists themselves deny all credit to the Trullan canons” (p. 63). Furthermore, and even more importantly, there were significant testimonies after the Trullan council rejecting the canonicity of the DC books. John of Damascus says that there are only 22 books. He explicitly excludes Wisdom and Sirach. Rabanus Maurus says also that there are only twenty-two books, and that Tobit, Judith, and the Maccabees do not have authority, though they can be read for instruction (see De institutione clericorum, chapter 54). Hugo of St. Victor also says that these books are read, but are not in the canon (Prolog. Lib. I. de Sacram. c. 7 and again in Didascalia, bk. 4, c. 8). Richard of St. Victor says the exact same thing (Exception. bk. 2, c. 9). So, even though the Romanist canon was supposedly fixed at the Trullan Council, there were several church fathers who rejected that canon even afterwards, and yet were never disciplined for it. So why would it be problematic to do so today? See Whitaker, pp. 63-66 for fuller argumentation.
When Was the Canon Fixed?