Upgrading to a new class. (Courtside Matters).

As in every profession, there are different levels of players in the NBA. There are stars, starters, rotation guys and the guys who want to be in the rotation. Usually, by the end of their third or fourth season, most players have settled into or are closing in on one of these groups. Once a player has carved his niche, it's difficult to move up to the next level. It happens, though, with a few players every year. This season has been no exception.

Gilbert Arenas, PG, Warriors. Since he broke into the lineup late in his rookie season, he has started every game. He has been as important as any player in the Warriors' turnaround. Arenas has few flaws in his game and none that can't be corrected over time. He's one of only a handful of players in the league who is averaging at least 18.0 points, 4.5 rebounds and 5.0 assists. It's pretty select company that includes Kobe Bryant, Kevin Garnett, Tracy McGrady and Chris Webber.

Chauncey Billups, PG, Pistons. Joe Dumars has to be pleased with this signing. Billups has had trouble in the past keeping a starting job, but he has been big for the Pistons. He can shoot 3-pointers and has the ability to penetrate and break down a defense. On a team without a true go-to player, Billups has come up big at the buzzer on numerous occasions.

Juwan Howard, SF, Nuggets. The Nuggets are a young team in the early stages of rebuilding. Howard is a veteran in the last year of a huge contract. He could have gone through the motions this season, but instead he has been the leader of that team. He's not going see another contract like the one that expires after this season, but there will be teams interested in signing him, partly because of the way he has handled himself.

Jamaal Magloire, C, Hornets. He has shown improvement across ...