Brady and J.J. Watt of the Houston Texans were the best players I saw on film through November, at which point the New England Patriots quarterback was No. 2 in Gregg Rosenthal's MVP forecast. Gronkowski went down the next week with a broken forearm, essentially sending Brady's aerial attack into a tailspin.
According to numbers compiled by NFL.com, Brady posted a 65.7 completion percentage, a 23-3 touchdown-to-interception ratio and a 106.6 passer rating with 7.9 yards per attempt on snaps with Gronkowski on the field. Those numbers plummeted to a 58.9 completion percentage, an 11-5 touchdown-to-interception ratio and an 87.1 passer rating with 7.1 yards per attempt on snaps without Gronkowski.
To be fair, Brady also was dealing with a hobbled Aaron Hernandez and Wes Welker in addition to the loss of Julian Edelman in early December. Still the effect of losing the NFL's best tight end and most dominant red-zone presence cannot be overstated. Since he entered the league in 2010, Gronkowski leads the NFL in red-zone touchdowns (29), quarterback-to-receiver completion percentage (72.2) and yards after contact per reception (2.54).
Brady's 2012 touchdown percentage was his lowest since 2009. His yards per attempt were at their lowest since 2008, and his completion percentage at its lowest since 2006.
Patriots fans always will wonder if Gronkowski's high-ankle sprain cost them a Lombardi Trophy against the New York Giants. They also might believe last year's AFC Championship Game would have played out differently if Gronkowski was available. Those two games are Brady's lowest-scoring of the past two seasons.
There's a lesson here for fantasy football leaguers as well. Saddled with a shaky receiving corps in addition to the cloudy nature of Gronkowski's early-season status, Brady is fighting an uphill battle for a fourth consecutive top-five finish.
Follow Chris Wesseling on Twitter @ChrisWesseling.