Gronkowski had reportedly been considering retirement and a potential move into acting or to the WWE, but those will have to wait, according to Rapoport.
The 28-year-old is set to earn a base salary of $8 million in 2018 and $9 million in 2019, according to Over The Cap.
A two-time Super Bowl champion, Gronkowski was named First-Team All-Pro for the fourth time in his career this past season, also making the Pro Bowl for the fifth time.
He caught 69 of 105 targets for 1,084 yards and eight touchdowns in 14 games. He caught nine of 15 targets for 116 yards and two touchdowns in the Patriots' Super Bowl LII loss to the Philadelphia Eagles.