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.