The Carolina Panthers continued their surprising spending spree Friday when they signed center Ryan Kalil to a six-year contract worth $49 million that will make him the highest-paid center in the NFL, according to team and league sources.

Kalil was scheduled to make $10.1 million in 2011 as the team’s designated franchise player and signed a five-year extension through 2016 that was restructured to lower his salary-cap number this year, sources said.

The deal includes $28 million in guaranteed money, sources told ESPN NFL Insider Adam Schefter. Kalil will make $30.75 million in the first three years, or an average of $10.25 million, even though the salary cap number will be lower than that.

Nick Mangold of the Jets became the league’s highest-paid center last August when he signed an extension that was valued at $54.075 million over seven years for an average of $7.725 million a season. Kalil’s deal would have to average around $8 million a year to top Mangold’s contract.

Kalil signed the contract before Friday night’s kickoff in Miami and the Panthers were expected to announce the deal, sources said.

After a flurry of free agent and trade activity that surprised many around the league, Panthers general manager Marty Hurney had identified Kalil’s long-term deal as his next priroity.

The Panthers transactions since the NFL lockout include re-signing its own pending free agents such as defensive end Charles Johnson (six-years, $72 million), running back DeAngelo Williams (five years, $43 million), linebackers Jon Beason (five years, $51.6 million), James Anderson (five years, $22 million) and Thomas Davis (five years, $12 million).

The Panthers also signed kicker Olindo Mare to a four-year, $12-million contract and added three tight ends in Greg Olsen (trade), Jeremy Shockey (free agent) and Ben Hartstock (free agent), among their other numerous transactions. The Panthers also made quarterback Cam Newton the No. 1 pick in the NFL draft and signed him to a guaranteed $22.5 million contract over five years.

Chris Mortensen is an ESPN senior NFL analyst. ESPN NFL Insider Adam Schefter contributed to this report.

Of all the exciting things Tampa Bay Buccaneers quarterback Josh Freeman already has accomplished, the one that is least noticed is the one that should prove most vital to the Buccaneers’ success this year. Along with producing impressive numbers and solidifying himself as a franchise cornerstone, Freeman, 23, has set a precedent. It’s fine to be a young player with plenty of promise, he seemed to be saying with his Pro Bowl-worthy play last season. Just don’t forget that being young isn’t a legitimate reason for having to wait on success.

That lesson will be essential to whatever the Bucs do this season. One of the NFL’s youngest teams went from being a three-win bunch in 2010 to a 10-6 squad last year, largely because Freeman developed so quickly that he tossed 25 touchdown passes and only six interceptions in his second year. What his maturation also did was give his teammates incentive to grow up in a hurry. It’s no coincidence that an offense that had as many as four rookies starting at one point — including wide receiver Mike Williams and running back LeGarrette Blount — managed to come within a whisker of qualifying for the wild-card spot that ultimately went to Green Bay.

That growth is what it takes to make people believe in a rebuilding effort. While someone has to be the centerpiece of the blueprint — Freeman, in this case — all the other rocks in the foundation have to see the importance of keeping pace. As Freeman said, “We are a hungry team. We want to be in the playoffs year in and year out. We want to be a team that is competing for championships, and not making the playoffs last season really stung.”

“Josh’s success really propelled everyone else,” said Bucs cornerback Ronde Barber. “When you get a group of young guys together — and it was the same back in 1996, ’97 and ’98 when I came here — those young guys start to see one or a few guys playing well and then everyone wants to play well. Josh’s success really influenced guys like Mike Williams and LeGarrette Blount. They’ve got a great bond because they’re all young and they want to grow in this thing together.”

As much as we talk about the importance of veteran leadership in the NFL, the kind of chemistry the Bucs are building is even more dangerous. It can sustain itself longer because players aren’t going to retire as quickly or move on in free agency as readily. It can be more beneficial to an organization because a strong culture is bred with every year the group spends together. It’s the kind of scenario most general managers covet. Once the young talent gains confidence and experience, the rest is a matter of maintaining consistency and drive.

As Barber noted, the Bucs struck gold in the 1990s when a group of green, gifted defenders — including defensive tackle Warren Sapp, linebacker Derrick Brooks and safety John Lynch — formed a foundation that eventually led to a Super Bowl-winning season in 2002. The Indianapolis Colts have won more games than any franchise over the past decade mainly because quarterback Peyton Manning started things off with wide receiver Marvin Harrison and running back Edgerrin James back in the day. And before that bunch, there were the three-time Super Bowl champion Dallas Cowboys led by Troy Aikman, Emmitt Smith and Michael Irvin.

Of course, there have been similar stories throughout the history of the league, but they’ve been harder to come by in recent years. The combined realities of the salary cap, free agency and fatter contracts make it harder to build what the Bucs are assembling. Plus, you have to get lucky every now and then. As the Bucs would admit, they’ve enjoyed pretty good fortune when it comes to the risk-taking department.

You want to know why the Bucs have something special? It starts with Freeman, a quarterback who was considered a first-round gamble by many people, even the very Bucs fans who booed his selection in 2009. There’s also Williams, a player who had 964 receiving yards and a team-record 11 touchdowns last season after falling into the fourth round because he quit the team at Syracuse. Finally, Blount was the franchise’s biggest success story last year. Maligned for a suspension that cost him nearly all of his senior season at Oregon, he went undrafted and was cut by Tennessee before gaining 1,007 yards in Tampa.

What all these players have in common is the same desire that can drive the Bucs for years to come. “When you think about Josh, our younger guys are looking at him and thinking why can’t they be good right now too,” Bucs general manager Mark Dominik said. “There’s no reason you have to wait until Year 2 or 3 to do that. Those younger players really believe in that because they see Josh doing it.”

The hope for the Bucs now is that more young players follow the example their star quarterback has set. They need young defenders such as Gerald McCoy and Adrian Clayborn to become dominant linemen, and they need a relatively older one, fourth-year cornerback Aqib Talib, to realize the obvious benefits of avoiding off-the-field trouble. They need their less-heralded players to embrace their roles and a few more hidden gems to materialize on the roster. More than anything, they need to remember how much it hurt to fall short of a playoff spot in 2010 … and how nobody is going to underestimate them this fall.

That’s the predictable price every team pays for enjoying a little success in the league. In the Bucs’ case, it shouldn’t change their overall fortunes. They’ve got a star quarterback, plenty of supporting talent and a greater understanding of what they can do in this league. They also have something else: the confidence that comes from knowing that youth really isn’t a barrier to anything they want to accomplish at this level.

Senior writer Jeffri Chadiha covers the NFL for ESPN.com.