Things will get more real for the Falcons under the lights Friday night.

The team’s practice at City Park Stadium in Gainesville will feature a scrimmage period with live tackling. There will be limitations such as no blocking or tackling below the waist, but it will be a change for the Falcons after lots of non-contact practices in helmets and shorts.

“It will look at some points very similar to what you’re seeing out here (during practices), but there will be times when we’ll allow the guys to go,” Falcons coach Mike Smith said.

Smith said the scrimmage will be 30 to 45 plays long. Coaches will get to evaluate players in game-like conditions for the first time during camp.

There’s competition at a handful of positions, particularly on defense, where the Falcons are working in new players at cornerback and defensive end.

“I guess that will be their first opportunity to kind of see what they do under the lights,” Falcons defensive coordinator Mike Nolan said. “There aren’t a lot of (fans) out there, but there are enough, (and) that’s a different environment for the guys. You’d like to see them up their game because there’s not a do-over. Out here we can say, ‘Hey, line it up, do over.’ It won’t be that way (Friday).”

Cornerbacks competing: The expectation is that rookie cornerback Desmond Trufant, the Falcons' first-round draft pick, will start opposite Asante Samuel at cornerback. But Nolan said it's possible that second-round pick Robert Alford could win the spot.

“Oh, yeah, no question,” he said. “The two young corners are providing a lot of competition there.”

Nolan said Trufant is “doing a very good job for a rookie.” He said he believes Trufant has adjusted quickly to the NFL because he can draw on the experiences of two older brothers, Marcus and Isaiah, who play in the league.

“He’s picking up things well,” Nolan said. “He’s an intelligent player; we knew that when we drafted him. Physically he’s gifted, as well.”

The reality for the Falcons is that both Trufant and Alford will have to play key roles because there are no other options.

“We are going to need them to play and play a lot,” secondary coach Tim Lewis said. “It’s no secret. Everybody in the league knows that we lost three (cornerbacks) to free agency. We acquired four (defensive backs) in the draft. So we’ll be relying on those guys to get up to speed early, and they’ll hopefully contribute a great deal to our success.”

The other two draft picks Lewis referred to are safeties Kemal Ishmael and Zeke Motta. Both were selected in the seventh round.

Inside move: Cliff Matthews, primarily a defensive end during his first two seasons with the Falcons, gained weight during the offseason at the team's request so he can play on the interior regularly this season. Matthews played inside on passing downs during the playoffs last season.

“He’s playing some roles that require a bigger guy,” Nolan said. “He’s bigger. He’s stronger. … I’m excited about Cliff. He’s a good, tough, good hand to have around. We will see how he does with the bigger size.”

Matthews said he gained about 10 pounds by working out and improving his diet and is now about 280.

“I think it’s working out good,” he said. “It’s something I had to do, and I did it.”

Early returns: Special-teams coach Keith Armstrong said there's "a pretty good chance" that Alford will get a chance to return punts and kicks. The other candidates are Jacquizz Rodgers for kick returns and James Rodgers and Dominique Franks to return both punts and kicks.

Wide receiver Harry Douglas was an effective punt returner as a rookie in 2008 and handled the duties at times last season when the Falcons needed a sure-handed returner. But Armstrong said the injury risk for Douglas, the No. 3 receiver, means it’s unlikely Douglas would return punts regularly.

“I think the one thing we’ve got to evaluate is where he fits in, when do you want to use him and have a plan and when and how we want to use him,” Armstrong said. “The rest is for coach Smith to decide.”

Roster moves: The Falcons waived injured cornerback Saeed Lee, who suffered a knee injury during practice Wednesday that required surgery. The team signed cornerback Jordan Mabin, who most recently played in the Canadian Football League. Mabin wasn't drafted in 2012 out of Northwestern and spent time in camp with Baltimore last summer and was on Cleveland's roster in December.