Tom Silverstein

Milwaukee Journal Sentinel

CANTON, Ohio - When he signed with the Green Bay Packers as an undrafted free agent in May, Joe Callahan figured he would be fighting for reps in training camp.

He’s not.

Instead, he’s going to start in his first NFL game.

Callahan will be under center when the Packers' offense takes its first snap against the Indianapolis Colts Sunday night in the Hall of Fame game, according to a source who was informed of the decision.

Related: Rookie QBs will achieve NFL dream Sunday

Related: Walden reunion awaits vs. Colts

That means coach Mike McCarthy has decided to play it safe and hold his starter, Aaron Rodgers, and backup, Brett Hundley, out of the first of five exhibition games for the Packers.

Rodgers is perfectly healthy, but McCarthy doesn’t want to expose him to any unnecessary risk on what is basically a high school field where last year the Pittsburgh Steelers lost kicker Shaun Suisham to a season-ending knee injury. They blamed the injury on the 11-year-old turf.

However, the Field Turf surface has been replaced as part of the stadium’s $80 million renovation with a surface known as UBU turf that was removed from the Superdome after the 2016 Sugar Bowl. A new permanent surface will be installed in Phase Two of the renovation, which begins shortly after the Packers and Colts play.

McCarthy also will take no chances with Hundley, who injured his ankle in practice Monday and has not taken any snaps in practice since. Hundley would have taken the most snaps in the game if he had been healthy.

Callahan said this week that he would try to control his nerves the best he could.

“First NFL snap, there’s definitely going to be some nerves but then there’s going to be a lot of excitement, too,” he said. “I’m going to try and make sure I’m level-headed and calm so I’m not firing the ball all over the place.

“That’s one of the things: Don’t let my emotions get the best of me.”

The Packers overlooked the fact that Callahan is just 6-foot-1 and signed him on the basis of his prolific college production. In four years as a starter, he completed 64.2% of his passes for 12,878 yards and 130 touchdowns with 38 interceptions.

He finished his senior season at Wesley with 5,063 yards and 55 touchdowns, becoming the first player in Division III history to throw for more than 5,000 yards and only the second player in college football history to reach that mark.

The Packers thought Callahan, who is a good scrambler, could help their defense prepare for some of the mobile quarterbacks they’ll face this season. Callahan is a project and probably will have to spend the year on the practice squad, but if he outperforms expectations, he could force the Packers to keep him on the 53-man roster or risk losing him.

Callahan has a high football IQ, but he is learning a new system and new mechanics and is facing a completely different level of athlete in the NFL. The Colts are expected to start the game with their No. 1 defense and so the challenge will be enormous for Callahan.

McCarthy gave Callahan the majority of snaps toward the end of the week, holding Rodgers out of practice on Thursday night. He is keeping his fingers crossed the rookie is far enough along that he can run the offense with some kind of efficiency.

In order to give Callahan a chance, McCarthy will probably have to use his starting offensive line – or at least a portion of it. If he can keep Callahan protected, then the rest is in the rookie’s hands.

“As the quarterback, I’m the one giving the athletes the ball,” Callahan said. “My play will also affect theirs, so I want to make sure that I’m going through my reads and progressions and getting the ball out to the receivers and making sure I’m putting the running backs in the best play possible, as well.”

Rookie Marquise Williams will follow Callahan, although when that will occur isn’t clear. Williams is behind Callahan in development but he will be playing mostly against third- and fourth-teamers so his challenge shouldn’t be as great.

Williams, signed on May 26 after the Packers gave up on Miami quarterback Ryan Williams. He started 33 of 48 games at North Carolina and set school records for rushing touchdowns (20) and yards (2,458) by a quarterback.