TAMPA, Fla. -- A football rests in Kwon Alexander's locker at One Buc Place, its presence a symbol of personal growth and pride. It's from his first career NFL interception, and if the Tampa Bay Buccaneers' rookie linebacker continues to flash, more mementos could be on the way.

"I really was trying to make a big play because we needed the energy and the momentum," Alexander said of his diving pick of Houston Texans quarterback Ryan Mallett last Sunday. "As soon as I saw [teammate] Danny Lansanah hit the ball, I was like, 'Oh, there's a chance.' I just dove and I caught the ball."

Sequences like that have allowed Alexander, a fourth-round pick out of LSU, to catch his coaches' attention. He was named the Bucs' starting middle linebacker in the preseason, beating out free-agent signee Bruce Carter, a five-year veteran. Against Houston in Week 3, Alexander had the best game of his young career, posting 10 tackles with two passes defensed and the interception. He has 23 tackles with four passes defensed and one interception this season.

It's obvious the Bucs view Alexander as a potential difference-maker and want him on the field as often as possible. He and linebacker Lavonte David, a pillar of Tampa Bay's defense since being drafted in the second round in 2012, are the only two players who have participated in each of the Bucs' 230 defensive snaps this year.

All the work remains exciting for Alexander, who approaches his role with youthful joy.

"Playing every snap, it's a lot," said Alexander, 21. "But I can do it, and Lavonte can do it. Most of all the linebackers can do it on the team. We've got a lot of stamina. ... When you enjoy the game and you're having fun, you don't even keep up with how many snaps."

Alexander's endurance should be tested in a large way Sunday against the Carolina Panthers. Quarterback Cam Newton has the potential to do damage with his arm and legs, and tight end Greg Olsen's athleticism poses a challenge.

Coach Lovie Smith knows Alexander's education will continue.

"Big challenge, one that as a rookie, you are looking forward to," Smith said. "Greg Olsen is an outstanding tight end. He can do an awful lot. Kwon knows that, so he knows that will be tough duty. Of course, they have other offensive players too, so he's looking forward to it."

To Bucs coaches, Alexander's speed and field awareness give him a desirable combination of athletic skill. Both traits could become assets Sunday and beyond as he continues to develop.

"To have a guy like Kwon who has tremendous athletic ability and can run with some of these quicker, twitch tight ends, we hope that it's in our favor," Bucs defensive coordinator Leslie Frazier said. "And he'll definitely be tested this week.

"He's improving. We've still got some things that we want to get ironed out, but some of that will come with experience."

With experience, Alexander has the potential to show more. But for now, he's enjoying a journey that has only begun, with his destination potentially exciting.

"I'm happy to be here," he said. "I'm happy Tampa Bay gave me the opportunity to come here and play ball. ... I'm just trying to get better and better every day."