Then they're 3-3. Eagles and Bills x 2, with losses to KC, Houston, and Baltimore.
Yes, Miami did go 5-4, and they came to play in a game that mattered a ton more to NE than it did to Miami. In that 5-4 stretch, Miami got BTFO by the Bills 37-20, Browns 41-24, and the Giants 36-20. Even with Flores being familiar with NE, there is no excusing this loss with the talent disparity.
NE's 4-4 in the second half is the most troubling part. Perennially they start slow and people start saying "Is this the end of the dynasty?" This time they started strong and are finishing weak. The offense should have pulled it together by now and they haven't.
Lastly, if you haven't, go watch Titans highlights with Tannehill. It doesn't show in the stat lines; he is throwing darts into tight coverages, vastly improved his pocket presence, and is making/extending plays with his feet. Combine that with Henry and AJ Brown and an upset is not out of the question.
I would not be surprised if NE wins, but this is the weakest offense NE has had this decade. If they could have fixed it, they wouldn't have waited until week 17 or Wild Card Weekend to do it.