Rob Gronkowski Still Mulling Retirement

Rob Gronkowski of the New England Patriots walks off the field after his team's 41-33 loss to the Philadelphia Eagles in Super Bowl LII at U.S. Bank Stadium on February 4 in Minneapolis. The Philadelphia Eagles defeated the New England Patriots 41-33. Kevin C. Cox/Getty Images

Rob Gronkowski is yet to make a decision over his future, fueling rumors he could opt to retire before the regular season begins.

The New England Patriots tight-end's future has been subject to speculation since he admitted he was contemplating retirement after the Patriots lost the Super Bowl against the Philadelphia Eagles in February.

After last season's finale, Gronkowski declined to commit to playing football in 2018 and, according to ESPN's Adam Schefter, he will not be attending the Patriots' first training session of the season on Monday.

Like Patriots’ QB Tom Brady, TE Rob Gronkowski will not attend the start of New England’s off-season program Monday, per source.

Gronkowski still is considering whether to play the upcoming 2018 season, and has had “good communication” with the Patriots, per source.

— Adam Schefter (@AdamSchefter) April 15, 2018

While attendance to the first day of the workout sessions is voluntary—Tom Brady will also miss the first day of the program as he is traveling with his family—Gronkowski's absence suggests he still has not made his mind up about his future.

This year, on top of a base salary of $8 million, the 28-year-old has a $250,000 workout bonus, which normally requires him to participate in the majority of training sessions during the off-season. Schefter added that the former Arizona student has had "good communication" with the franchise over the last couple of months but it remains to be seen whether he will extend his stay in New England.

The New York state native has been beset by injuries—he has only managed to start all 16 regular season games once during his eight-year spell with the Patriots—and his fitness will play a major role in deciding his future.

Earlier this month, ESPN's Jeff Darlington reported sources close to the player had hinted Gronkowski was "pretty certain" he would come back as long as Brady remains with the team.

However, the sources also admitted the situation was complicated by a difficult relationship with coach Bill Belichick, who has reportedly questioned whether Gronkowski remains fully committed to the cause after admitting he had considered retiring.

One person who does not seem to be overly concerned by Gronkowski's future is Patriots owner Robert Kraft, who claimed the prospect of being without the two-time Super Bowl winner was nothing to be afraid of.

"It's not even an issue for me," Kraft was quoted as saying by The Athletic on Thursday.

"I didn't know about it until I read about it in the paper. I saw him [recently at Gillette Stadium]. We have a fun, good relationship. He is one of the most up people I know. I was impressed that he was coming in late and doing whatever he had to do to make himself feel right and get his body right."