In the first half of his team's game against the Jets, Gronkowski exited the field and went back to the locker room with what the Patriots called a back injury. His return to the game was initially deemed questionable, but he was downgraded to out after halftime.
It's not clear when Gronkowski aggravated his back. He was targeted twice deep down the field, but both plays resulted in incompletions. On one of those deep balls, Gronkowski ended up going to the ground, but he didn't leave the game after that play. For all we know, it could've happened on a play that didn't directly involve him.
Regardless of the cause, Gronkowski can't catch a break. He missed the first two games of the season with a hamstring injury and then endured a huge shot from Seahawks safety Earl Thomas a couple weeks ago, which resulted in a one-game absence.
When he's been on the field, he's been as explosive as always, catching 25 passes for 540 yards and three touchdowns. But he just can't seem to stay healthy. Adding to the concern is the fact that Gronkowski has a history of back injuries. Gronk revealed last year that he considered retiring from football in college after suffering a serious back injury while lifting weights.