According to NFL Network's Michael Giardi, some inside the Patriots believe that if Gronkowski "had done it their way as opposed to the TB12 way" the five-time Pro Bowler may have stayed healthier.
The Providence Journal's Mark Daniels noted in January 2018 how Gronkowski had altered his offseason training regimen to mirror Brady's workouts and preparation with trainer Alex Guerrero:
"Following his back surgery, Gronkowski made sweeping changes in the way he ate, trained and lived. He started working at the TB12 Center with Brady's trainer Alex Guerrero in March. Gronkowski's new diet was full of water, electrolytes, plant-based protein and essential fats. For the first time in his life, he embraced healthy eating — or has at least tried his best."
Last month, former NFL tight end Christian Fauria was critical of the approach and thought the workouts in particular didn't match with the physical demands of the tight-end position.
"The right weight room is the one [Patriots strength trainer Moses Cabrera] is overseeing," Fauria said on his WEEI radio show. "You're squatting, you're benching, you're working on explosive power. You can't play tight end in this league and just work with bands."
Gronkowski's stats don't paint the TB12 Method in a positive light. He finished with 47 receptions for 682 yards and three touchdowns. His 52.5 yards per game were his lowest since his rookie year in 2010.
The 29-year-old also dealt with back and ankle injuries, missing three games and only making 11 starts.
Gronkowski's relationship with Brady and Guerrero off the field may not be a concern for the Patriots for much longer, though, with some level of doubt surrounding his status for the 2019 season and beyond.