Since 2007, Washington Redskins inside linebacker London Fletcher has been the heart of the Redskins defense, going to four-straight Pro Bowls and leading the NFL in tackles.
While he may seem ageless, the Redskins front office understands that the day will come when No. 59 will no longer impose his will in the middle of the defense.
When that day comes, look for fellow inside linebacker Perry Riley to take the torch, as he has already started carving out a fierce reputation of his own.
In 2012, Riley was quietly one of the most productive linebackers in football, finishing the regular season with 129 total tackles, which ranked 14th in the NFL, and second on the team.
The former LSU Tiger was thrust into a starting role for the last eight games of the 2011 season, and has since solidified the Redskins Jack linebacker position. And since then, the team has found that Riley has made his most significant leap in his understanding of the system.
"I think his biggest jump has just been from the mental aspect of it," Fletcher said. "Understanding the defensive scheme, knowing his responsibilities like the back of his hand."
"Initially when he became the starter half way through the  season—you don't get a lot of reps as a backup linebacker. So he was almost thrown in the fire midway through the season. There's a learning curve that takes place.
"But having gone through a couple full off-seasons, knowing that he's going to be the starting linebacker, his game has just elevated."
"I think he's really on the verge of making that next step into being our [best] inside linebacker."
Fletcher added that if needed, Riley could fill in to play Fletcher's Mike linebacker position as well, explaining that different situations can dictate who plays which role.
With Riley's rapid improvements, the Redskins brass has heightened their expectations for the fourth year veteran.
"Perry Riley is very impressive," said head coach Mike Shanahan. I think he gets more comfortable with the defense every year, and we put a lot more pressure on him."
"With linebackers, you look for quickness and speed – and he has both of those qualities," Shanahan added. "He's got excellent speed, excellent lateral movement and he's an athlete. So hopefully, he makes a big jump this year, but he's been playing well for us."
Riley's performance in his first 24 starts has been overshadowed by Fletcher's extraordinary ironman streak, but on tape, there is no questioning his ability.
"If you really study Perry Riley on film and you just looked at him, you'd say, 'Boy, this is one of the fastest linebackers in the league," Shanahan said. "He's very physical.
"I expect Perry to have an excellent year this year."