FLOWERY BRANCH — Spencer Adkins didn’t need official confirmation.

The Falcons linebacker knew right away he was about to step from his reserve role to starter, all in the spotlight of the NFL playoffs.

When Adkins reported to work following last month’s loss to the Saints, he learned Mike Peterson was out for the final game of the regular season and the postseason with a torn triceps. As it was, Peterson was subbing for the injured Stephen Nicholas, whose toe injury likely will keep him out of Sunday’s playoff opener against the Giants.

“I already knew,” Adkins said. “Nobody had to tell me a thing. ... When somebody does go down, you have to be able to come in and act like there is not a difference.”

Adkins made his first career start Sunday against the Buccaneers in the regular-season finale. He finished with a career-high three tackles in a Falcons victory that secured the No. 5 playoff seed. While Nicholas worked with trainers Friday, he is listed as doubtful for Sunday’s game. So Adkins’ second career start likely will come this weekend.

“We’ve got all the confidence in the world that Spencer can step in and play the role that Stephen Nicholas has,” coach Mike Smith said. “That’s the great thing about having depth on your football team. That’s why the guys are on our roster. They’re on our roster to have an opportunity to go out and play, and when they’re called upon, we’re expecting them to play at the level or just as good as at the level of the guy that was in front of him.”

Adkins says he is no stranger to playing in big football games. He played in state championships at Naples High School in Florida. He went on to play at the University of Miami. After being drafted in the sixth round (No. 176 overall) in 2009 by the Falcons, Adkins has waited for his opportunity. He has played on special teams and on a limited basis at linebacker in his three seasons.

“I’m looking at it like just another game,” Adkins said. “I’m not putting too much weight on it, even though there is. The way I take it is, it’s just another game. You still have to do the same things you would do in a regular-season game. You have to prepare to win and do the smart things. That’s what I’m going to do.”

Peterson, a reserve much of the season, is unquestionably the vocal leader of the linebacker corps. He presided over the group’s corner of the Falcons locker room known as the D-Block. Adkins, whose locker is directly across from Peterson, said he has spent his time taking in as much knowledge as possible.

“I just sit behind all the guys, I watch them and I learn every day,” Adkins said. “I take it as an opportunity. I don’t think [I was] waiting [for an opportunity]. I learn from these guys so when my time did come, I was ready.”

Middle linebacker Curtis Lofton said Adkins played well in his first start.

“There really isn’t much drop off,” Lofton said. “Spencer’s been here three years; he knows the system. He just had to get the opportunity, and he got it and he’s been running with it.”