Veteran backup Jacoby Brissett, who took over in Tagovailoa's absence last Sunday, has officially been named as the Dolphins' starter for Week 3.
"We decided to run some more tests, we ran them, and we got this information," Flores said via Darlington. "It’s unfortunate. I don’t want to put a timetable on it. He’s taking it day to day."
Tagovailoa was limited to just four passing attempts before being injured during the Dolphins' loss to the Bills.
Brissett finished Sunday's game with 169 yards and an interception on 24 of 40 passing. The 28-year-old veteran enters Sunday's game with a 12-20 career record as a starter having previously made two starts for the New England Patriots (2016) and Indianapolis Colts (2017, 2019).
Tagovailoa threw for 202 yards on 16 of 27 passing, as well recording two touchdowns (one passing, one rushing) and an interception during a 17-16 win against the AFC East rival New England Patriots in Week 1.
The debut performance came after months of speculation that the Dolphins weren't totally sold on the former University of Alabama standout as their franchise quarterback amid inconsistent performances during his rookie season.