The Patriots previously paid $4 million of Gronkowski’s $10 million option bonus back in August, according to Rapoport.
This appears to be a precursor to extension talks between New England and Gronkowski.
Gronkowski, 26, is entering the fifth years of his eight-year, $55.23 million contract that included $13.17 million guaranteed. He’ll make a base salary of $2.25 million for the 2016 season.
In 2015, Gronkowski appeared in 15 games for the Patriots and registered 72 receptions for 1,176 yards receiving and 11 touchdowns. Pro Football Focus has him rated as the No. 1 tight end out of 67 qualifying players.