FLOWERY BRANCH — Offensive guard Mike Johnson, who suffered a concussion, will not play against Miami in the exhibition opener at 7:30 p.m. Friday at the Georgia Dome.

Johnson is in a battle with Garrett Reynolds to start at right guard. He has not practiced since he suffered the concussion Aug. 4.

“He’s not been cleared to come back and play,” Falcons coach Mike Smith said Wednesday. “Right now, Garrett Reynolds will get a jump up in the evaluation process.”

Neither player has started an NFL game. The winner of the competition will replace Harvey Dahl, who signed with the Rams during free agency.

“That guard spot is one that we’ve got to come to a conclusion on, and that’s what’s going to happen over the next four weeks,” Smith said.

Johnson, center Joe Hawley (knee) and tight end Marquez Branson (knee) all worked off to the side with members of the training staff. Defensive tackle Vance Walker (right ankle) did not practice.

Bosher a triple threat

Matt Bosher, who was selected in the sixth round of the draft (192nd overall), will be a busy against Miami.

He’s set to handle the punting, kickoff and holding duties.

“I can assure you, he’s going to be a little bit nervous this Friday night for his first real test,” Smith said. “He’s done a nice job up until this point.”

Bosher is in a battle with Ken Parrish to replace Michael Koenen, who signed with Tampa Bay during free agency. Parrish was in camp with San Francisco in 2007 and was signed as a free agent on March 3. He last punted in the UFL in 2010.

“Everybody knows when the punter or the holder or the kickoff guy doesn’t do his job,” Smith said. “I’m anxious to see how he handles the pressure.”

Clabo on drug testing

Right tackle Tyson Clabo, the team’s union representative, believes that teams will adjust if new game-day drug testing rules are implemented.

“At first, there are going to be some guys that bark about it and complain,” Clabo said. “But at the end of the day, it’s going to be one of those situations where we’re going to have to adjust, however it goes down. We’ll adjust, and it won’t be the end of the world.”

The NFL and the players’ union are still working out how to test for human growth hormone.

“From what I understand from the talks, why we didn’t think it was necessary really to start doing that, was because it’s out of your system really fast and it’s hard to find,” Clabo said. “You’d have to be doing it the day before.”

Bush in nickel mix

Secondary coach Tim Lewis said that Rafael Bush, who’s listed as a safety, is in the mix to win the job at nickel back. He’s battling cornerbacks Christopher Owens and Dominique Franks.

“Those three guys are working the nickel spot right now and getting as many repetitions as the rules allow,” Lewis said.

Bush, who signed as an undrafted free agent from South Carolina State in 2010, was on the practice squad last season.

Etc.

Running back Michael Turner was excused from two days of practice for personal reasons. Turner took part in the afternoon practice and is slated to play against Miami. ... The Falcons’ first-team defense will be tackling live for the first time Friday night. ... Practice had a little NBA flavor when Oklahoma City Thunder general manager Sam Presti stopped by the morning session. He was as a guest of general manager Thomas Dimitroff.