However, I'd like to provide some corroboration by Roman Catholic scholars Raymond Brown and John Meier, whose book received both the Nihil Obstat and the Imprimatur (bold mine):
There is no doubt that it [The Shepherd of Hermas] was written at Rome (Vis. 1.1.1.; 2.1.1; 4.1.2); and the suggestion that Clement would send it abroad (Vis. 2.4.3) may mean that Hermas' revelations had church status in Rome...[characterizing the letter] Bernard ("Shepherd" 34-35) may be closer to the mark: "Thus I Clement, like Hermas, is a Christian work which leans heavily on late-Jewish and early Jewish-Christian tradition and apologetics, and this raises the question as to the composition of the Roman Church in the late first and early second centuries. There would appear to be grounds for thinking that the influence of the Jewish-Christian element in the Church remained strong into the second century." I would rephrase slightly, for I think of Rome as containing a dominant Jewish/Gentile Christianity that had strong loyalties to Jerusalem and the Jewish tradition. The author of Hermas may have been ethnically a pure Gentile, but he would be representative of that continuing strain of Christianity. The indication that there was still a church structure of presbyter-bishops and deacons433 indicates how conservative the Roman church was.1
The footnote (#433) referenced above reads (bold mine):
433. See p. 163 above. All the references to presbyters and bishops are in the sections that some would judge chronologically early. However, if the men sitting on the bench in Man. 11.1 are presbyters, then the structure of presbyter-bishops lasted into the 140s. Telfer, Office 61, however, thinks it unquestionable that by the time Hermas was finished there was a single-bishop at Rome.2
Page 163 (and the previous page) reveals the following discussion (bold mine):
An older generation of Roman Catholic scholars assumed that the single-bishop practice was already in place in Rome in the 90s or earlier; and they opined that, as fourth pope (third from Peter), Clement was exercising the primacy of the bishop of Rome in giving directions to the church of Corinth. The failure of Clement to use his own name or speak personally should have called that theory into question from the start, were there not other decisive evidence against it. As the ecumenical book Peter in the New Testament (done by Roman Catholics and Protestants together) affirmed, the connection between a Petrine function in the first century and a fully developed Roman papacy required several centuries of development, so that it is anachronistic to think of the early Roman church leaders functioning as later popes (see footnote 275 above). Moreover, the Roman episcopal list shows confusion...All of this can be explained if we recognize that the threefold order of single-bishop, with subordinate presbyters and deacons, was not in place at Rome at the end of the first century; rather the twofold order of presbyter-bishops and deacons, attested a decade before in I Peter 5:1-5, was still operative. Indeed, the signal failure of Ignatius (ca. 110) to mention the single-bishop in his letter to the Romans (a very prominent theme in his other letters) and the usage of Hermas, which speaks of plural presbyters (Vis. 2.4.2) and bishops (Sim. 9.27.2), make it likely that the single-bishop structure did not come to Rome till ca. 140-150.3
1. This work received both the Nihil Obstat and the Imprimatur. It therefore carries more general weight than those whose only qualifications as Catholic apologists are a keyboard and an internet connection.
2. Brown and Meier are established Catholic scholars. They therefore carry more weight than otherwise unknown lay-Catholic apologists on the subject.
3. Brown and Meier state their position in direct contrast to previous generations of Roman Catholic scholars. Even on something as important as the nature of the church government of Rome, with particular application to the power and authority of the bishop(s) there, Catholic scholarship has not been consistent. This observation plays into a variety of problems with Roman Catholicism, some of which are fairly obvious.
4. There are lay-Catholic apologists who object to the term "Roman Catholic." This, however, is how Brown and Meier both refer to themselves and previous generations of scholars within their own denomination. If it's acceptable for Brown and Meier, and morally consistent with Catholicism proper (via the Nihil Obstat and Imprimatur), it should be acceptable to lay-Catholic internet apologists.
1. Antioch and Rome: New Testament Cradles of Catholic Christianity (Mahwah, NJ: Paulist Press, 1983, 2004), 203-204.
2. Ibid., 204.
3. Ibid., 162-163.