"It's not even an issue for me," Kraft told Jeff Howe of The Athletic. "I didn't know about it until I read about it in the paper. I saw (Gronkowski 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."
Gronkowski has appeared somewhat uncertain about his playing future since Super Bowl LII - which New England lost to the Philadelphia Eagles - with several factors potentially contributing to the tight end's reluctance to commit to a ninth NFL season.
"I think (Gronkowski) is the best tight end in the game, maybe in the history of the game, so we're privileged to have a quarterback (in Tom Brady) and tight end in those positions," Kraft added. "I do believe, though, people feel differently (after a loss). That was a tough loss. We'll let things sort out and see what happens."
Though he's still in his prime and one of the NFL's most dominant players, Gronkowski has dealt with numerous significant injuries during his career that could be starting to wear on him. The 28-year-old also reportedly caught flak from Patriots coach Bill Belichick last year for working with Brady's personal trainer, Alex Guerrero.
Despite missing two games, Gronkowski led New England in receiving during 2017 with 1,084 yards, and in touchdown receptions with eight.