Gronkowski, 29, had been listed as questionable with added "concern" about whether he would play, as Adam Schefter of ESPN reported earlier in the day.
The oft-injured Pro Bowler already missed one game this season because of a back injury. His backup, Dwayne Allen, did not record a single reception in the win over the Chicago Bears.
From a fantasy perspective, there's little use in picking up Allen. Gronkowski has not been getting his typical red-zone targets, and Allen isn't going to suddenly start picking them up in his stead. If you're desperate in a deep league, Allen could be worth a pickup. Odds are there are better options hanging around, though—even at the shallow tight end spot.
James White, on the other hand, could have even more value. White has been Tom Brady's favorite underneath target all season and in some ways has usurped Gronk as his safety blanket. The running back has 55 receptions for 459 yards on the season, to go along with 204 yards on the ground.
White is probably starting on your roster already, so just keep deploying him as you would. He might just get an extra couple of targets to help his value in points-per-reception formats.