Adam Schefter of ESPN reported that Gronkowski will not attend the workout as he is "still considering whether to play the upcoming 2018 season".
This all began after the Super Bowl when Gronkowski wouldn't commit to playing in 2018.
Gronkowski reportedly grew exhausted of the "high-strung" culture within the Patriots organization. Some of the discussions have been focused on Gronk's contract.
"We have the voluntary offseason program that starts on Monday", he said. While most players are expected to report to the facility, they are not contractually obligated to do so.
With 474 catches for 7,179 yards and 76 touchdowns in his career through only eight seasons, the 28-year-old Gronkowski is already among the most productive tight ends in National Football League history. The workouts are voluntary.
Gronkowski joins teammate Tom Brady, who will also sit out the beginning of the offseason due to a business trip overseas.
Patriots coach Bill Belichick acknowledged on Friday that not all Patriots players would be present on Monday.