There will be ample opportunities for young players to make a name for themselves on defense for the Buffalo Bills in the 2013 season.

When the team jettisoned veterans Nick Barnett, Kelvin Sheppard, George Wilson and Terrence McGee in the offseason, it lost its three leading tacklers from last season, along with 385 combined games of NFL experience.

If the inexperience of those taking their place is a concern among the team’s fans, it doesn’t seem to be one shared by new defensive coordinator Mike Pettine. At least not publicly.

“It is a lot, and that was on purpose,” Pettine said of the workload he gave his players in spring practices. “I think as a coaching staff, we’re very optimistic with how this group learns. We’ve been able to handle a lot.

“What proves it even more is the up tempo. When an offense goes no-huddle, you don’t have those 15, 20 seconds in between plays to process and recall ‘what’s my job? What are my main coaching points here?’ You’ve got to know it, and I think our guys have really taken that to heart. I’m very pleased with where we are mentally.”

Rookie second-round draft pick Kiko Alonso has the inside track heading into training camp on replacing Barnett, who led the Bills with 112 tackles last season and played about 92 percent of the defensive snaps. Both Pettine and coach Doug Marrone have been pleased with Alonso’s development.

“I think Kiko has done an outstanding job, he really has,” Marrone said. “There’s been a little bit of ups and downs, but that’s not a knock on him. That’s what happens with young players. I’m extremely excited to see him perform when the pads come on.”

Assuming Alonso fills the role of an every-down linebacker, the question will be who joins him when the Bills go to a nickel (five defensive backs) formation, which Pettine has hinted could essentially serve as the Bills’ base defense.

The two favorites are second-year man Nigel Bradham and veteran Bryan Scott.

“Nigel can run. That’s the one thing we’re going to take advantage of,” Pettine said. “He’s explosive, so there are times if he’s a little slow to diagnose, he can make up for it with his speed. We’ve been real pleased with that. He’s been real coachable. It’s not often he makes the same mistake a second time.”

Scott, 32, is on a one-year contract. His playing time last season – about 54 percent of the snaps – illustrates why Pettine expects the Bills to be in nickel quite a bit.

Two players to watch in camp who could push Bradham and Scott for playing time are Marcus Dowtin – who has experience in Pettine’s system from his time spent with the Jets last season – and Keith Pough, an undrafted free agent out of Howard University who is a tackling machine.

“I feel good. That’s a solid room,” Pettine said of his linebacker depth. “We’re pleased with where that group is.”

At outside linebacker, the Bills added veteran Manny Lawson as a free agent. He missed most of the voluntary spring practices after his wife gave birth, but is expected to challenge for a starting role opposite Mario Williams. The biggest question behind those two is how the staff uses veteran Mark Anderson – who’s returning from a knee injury – and former Colts first-round draft pick Jerry Hughes, who was acquired in a trade for Sheppard.

Free agent Jamie Blatnick, who spent time last season on Denver’s practice squad, will push both Anderson and Hughes for practice reps.

Behind the linebackers, there are several positions up for grabs at camp. The biggest unknown is the status of Pro Bowl safety Jairus Byrd. If he reports on time, he can be written into the starting lineup in pen. But if Byrd, who has yet to sign his franchise tag tender, stays away, that means both safety jobs will be contested.

Wilson’s departure opens a spot in the lineup for Da’Norris Searcy, who split time at strong safety last season, playing about 25 percent of the defensive snaps. Searcy, though, figures to be pushed by fourth-round draft pick Duke Williams. True to their word when they drafted him, the Bills used Williams in a number of different roles in the spring, including at both safety spots and cornerback.

Without Byrd, the starting free safety spot would likely come down to converted cornerback Aaron Williams, a third-year player, or rookie Jonathan Meeks.

“I’d say he’s ahead of schedule. It’s a lot to take in,” Pettine said of Williams. “It is apples and oranges. Being a safety is such a different world from being a corner. There are a lot of plays where he ends up locked on a guy where his corner instincts can take over, but for the most part, it is a lot of learning and a lot of communication. He’s ahead of schedule of where we thought he would be.”

Also in the secondary, the battle for the nickel cornerback job should be close. The three primary candidates are second-year man Ron Brooks, third-year player Justin Rogers and undrafted free agent sleeper Nickell Robey out of Southern California.

Robey, who has the right name for the job, was impressive in spring practices, but will have to answer questions about his size (5-foot-8, 165 pounds) with the pads on. It’s clear, however, that he’s made an early impression, as General Manager Doug Whaley brought him up as a candidate for the job in an interview with the team’s official website.

Rogers, 5-11, 185, held the nickel job in the first half of 2012, but was eventually replaced in the lineup when Brooks returned from a broken foot.

Brooks is the biggest and fastest of the players competing for the spot, listed at 5-11, 188 pounds and timed in the 40-yard dash at the 2012 NFL Scouting Combine in 4.37 seconds. In his rookie season, he played in nine games, making two starts and finishing with four passes defensed.

Up front, the Bills added Alan Branch to a defensive line mix that includes Kyle Williams, Marcell Dareus and Alex Carrington in traditional 3-4 looks.

The Bills rotated Dareus with Jay Ross at times during spring practices. That’s a move that has all the signs of a motivational ploy for the former third overall pick in the 2011 draft.

The list of players looking to make a favorable impression on the new coaching staff starts with Torell Troup, a former second-round draft pick who missed all of last season on injured reserve after back surgery. This is likely his last chance to make it with the Bills.

Ross will compete with Jarron Gilbert and Corbin Bryant for reserve roles along the line. Bryant, a 330-pounder, got plenty of second-team practice reps in the spring.


Coming Tuesday: Offensive coordinator Nathaniel Hackett