Like many teams around the league, the New England Patriots are coming up on the start of their offseason program. Involuntary workouts begin Monday for the Pats, but when they get underway, two of the best players on the team will not be in attendance. 

According to's Adam Schefter, neither Tom Brady nor Rob Gronkowski will be there. Gronkowski also is still considering retirement, though he's been in communication with the team. 

As former NFL agent and current CBS Sports contributor Joel Corry noted, Gronkowski must participate in 90 percent of New England's offseason workouts in order to receive his $250,000 workout bonus. 

There have been rumors about Gronkowski's future swirling all offseason, with everything from retirement to a trade to returning to the team like nothing ever happened seemingly on the table. Gronk was reportedly frustrated with Bill Belichick last season and would return to the team only if Brady does as well, and it looks like that's going to be the case. The last update prior to this report was that Gronk was "pretty certain" he was going to play, so it's interesting to see that he's still apparently considering his options. 

Last week, Belichick told, "We have the voluntary offseason program that starts on Monday. It will be heavily attended, but I know there are a couple players that I've talked to that have other commitments, but that's the way it always is. So, not really anything new there."

New England has already lost several important offensive contributors this offseason, as Dion Lewis, Nate Solder, Brandin Cooks, Danny Amendola, and Cameron Fleming are all now playing for new teams. Losing Gronk would obviously be a much bigger blow to their chances. Skipping involuntary workouts isn't necessarily a sign that he won't be back, but it will start getting worrisome if he misses mandatory team activities.