Taylor Heinicke replaced Penix with 6:40 remaining in the second quarter.

Quarterback Tua Tagovailoa and receiver Tyreek Hill were among the veterans who weren’t in uniform for Miami. Tagovailoa signed a four-year extension, and Hill had his contract restructured during training camp.

Jason Sanders kicked field goals of 58 and 47 yards for the Dolphins, who took the lead for good with 14 straight points in the second quarter.

Skylar Thompson’s 6-yard touchdown pass to Jeff Wilson Jr. tied it at 10. Jaylen Wright then ran it in from 6 yards after linebacker Isaiah Mack recovered Heinicke’s fumbled snap.

Sanders and Koo converted field goals in the third quarter before Atlanta twice turned it over on downs inside the Miami 10 in the fourth quarter.

The Falcons initially plan to utilize Penix as an understudy to veteran Kirk Cousins, who signed a four-year deal in the offseason.

It is undetermined whether Cousins will take snaps during the preseason as he recovers from an Achilles injury that sidelined him the final nine games last season.

Cousins has participated in Atlanta’s training camp, including the two joint practices with Miami at the Dolphins’ facility this week.

While Penix played, edge rusher Chop Robinson, the Dolphins’ first-round pick, was not in uniform.