In Manachot 38b we see the following lines of Gemora (Translated by Soncino)
As the sons of R. Hiyya said, Curtailed blue threads are valid; curtailed hyssop twigs are valid. What is the minimum length of a curtailed thread? — Bar Hamduri stated in the name of Samuel, There must be sufficient to make a loop therewith. The question was raised: Does ‘sufficient to make a loop’ mean to make a loop of all the threads together, or of each thread separately? — This remains undecided. R. Ashi raised the question: How is it if [the curtailed threads] are so thick that one cannot make a loop with them, although had they been thinner one could have made a loop with them? — R. Aha the son of Raba answered R. Ashi, They are most certainly [valid], since the precept is all the more noticeable thereby
Who is the Tanna that disagrees with Rabbi? It is the Tanna of the following Baraitha. For it was taught: R. Isaac says in the name of R. Nathan who said it in the name of R. Jose the Galilean and who in turn said it in the name of R. Johanan b. Nuri, If a man has no blue threads he should insert all white threads.
Raba said, You can infer from this that one must make a knot after each joint; for should you hold that this is not necessary, then how could the sons of R. Hiyya have said, Curtailed blue threads are valid, also curtailed hyssop twigs are valid? As soon as the upper knot becomes loose it would all become undone! —
Now my question is: Why is the Italicized part of the Gemora placed between the two bolded parts? Shouldn't it come after the second bolded section or before the first?
Raba says "You can infer from this", but the "this" he is referring to, is obviously the first bolded statement, and not a reference to "Who is the tana". You would expect the "this" that Raba is referring to, to not be interrupted with unrelated material about the original mishna and the author of the anonymous opinion which disagrees with Rebbe.