The Patriots have certainly missed tight end Rob Gronkowski and it's easy to point to the red zone as the most important place of need. When the Patriots have Gronk, they've scored 19 touchdowns on 27 trips to the red zone. Without Gronk, they only have 10 touchdowns on 26 trips. That's a tremendous difference of nine scores.
What might be understated, however, is the total number trips: Gronk played half of the season and the Patriots have made it to the red zone roughly the same amount of times with and without Gronkowski on the field.
In fact, when looking at drive statistics, the Patriots have actually been fairly successful in moving the ball, regardless of Gronk's health status. The Patriots have had 83 drives with Gronkowski (that didn't end in a kneeldown) and 91 drives without Gronkowski. In both cases, the Patriots have had 31 drives of 50 or more yards, or a touchdown.
Yes, the Patriots offense is better with Gronkowski healthy. Yes, the Patriots move the ball between the 20s better with Gronkowski- however, the Gronk benefit is only marginal when compared to the value he presents in the red zone.
Tom Brady and New England will be fine moving the ball even if Gronk is on the sideline. The main focus should be on replacing his value in the red zone. Hopefully the return of Aaron Dobson can help spread the defense and open up lanes for the more shifty receivers to make plays underneath. Maybe Kenbrell Thompkins can emerge as a reliable red zone threat.
Whatever the solution, the Patriots need to come up with one, and quickly.