Heinicke returned to practice Thursday and is expected to start Sunday night's pivotal game at the Dallas Cowboys. After winning four consecutive games, Washington (6-8) has lost two in a row and likely has to win its final three games to have a shot at the playoffs.
Heinicke and backup Kyle Allen were placed on the reserve list last week and were among the 13 players and seven assistant coaches who missed the 27-17 loss Tuesday to the Philadelphia Eagles. The team had hoped one of them would be cleared in time for that game, but the expectation had always been they would return for the Dallas game.
"It sucked," Heinicke said. "I felt fine the first couple days, then the symptoms started coming in and It sucked there for a little bit. I'm happy to be back now. It's never fun sitting at home watching your guys play a game and you can't do anything about it."
He said he had a scratchy throat, a runny nose and body aches.
"I tried to do some laundry and put all the dry clothes in a big hamper and walked to the living room. It's 20 steps and I was out of breath," Heinicke said. "Headaches. But it finally went away yesterday."
Heinicke said he had a playbook binder open while watching Tuesday's game by himself at home since he was still testing positive.
He said it was good for him to return now, giving him two days of practice and a chance to recover.
"I could feel myself getting winded a little bit," he said of Thursday's practice.
Washington, who has 15 players on injured reserve, also has a home rematch against the Eagles and a road game at the New York Giants.
Heinicke had started every game since Week 1 starter Ryan Fitzpatrick was injured in the second quarter of the season opener. In 12 starts, Heinicke has thrown for 2,931 yards and 19 touchdowns with 12 interceptions. His Total QBR of 46.2 ranks 22nd among NFL quarterbacks.
Getting Mayo back is important because starting inside linebacker Cole Holcomb was placed on the reserve/COVID-19 list Wednesday.
Washington still has injury concerns on defense. Corner William Jackson III (ankle) and safety/linebacker Landon Collins (foot) were hurt in the game Tuesday. Neither one practiced Thursday. Safety Kam Curl and cornerback Kendall Fuller, both starters, remain on the COVID-19 list.