New England Patriots tight end Rob Gronkowski is back on the trading block until there's a resolution in his contract status, according to an AFC executive.

"Where's the restructure of his contract?" the executive said, per Greg A. Bedard of the Boston Sports Journal. (via WEEI's Ryan Hannable). "Until that's done, I think he's still available. I wouldn't be surprised if (Bill) Belichick is going to test Gronk's buy-in with the contract."

Gronkowski, 29, hinted at retirement after the team's Super Bowl 52 loss to the Philadelphia Eagles. Reports began to surface that he was unhappy playing under head coach Bill Belichick, and Gronkowski was mentioned heavily in trade rumors before and after the NFL draft.

The two-time Super Bowl champion signed a six-year extension worth $54 million in 2012, which is now a major bargain for the Patriots. Gronk will make just $8 million in 2018 and $9 million the following season, per Spotrac.com.

Gronkowski hasn't taken part in the team's offseason workouts, a clear sign that he wants a new contract. But Belichick has a long history of parting ways with key players if they demand too much money.

Most recently, standout defensive players Jamie Collins, Chandler Jones and star receiver Brandin Cooks have been dealt in their contract years by Belichick, who opts to receive draft picks rather than pay top dollar for some of his top talents.

Gronkowski has been the NFL's best tight end since he broke into the league eight years ago. He has 76 career touchdown receptions in just 102 games, and has been named to five Pro Bowls.

Trading Gronk would undoubtedly hurt New England's chances of winning another Super Bowl, but Belichick has found countless ways to replace elite talents. Nobody in Foxborough should doubt Belichick, but trading the league's top tight end in his prime would still cause plenty of eyebrow raising.

NEXT: JOHNNY MANZIEL FOCUSING ON RECOVERY IN CFL RUN WITH TICATS