A month has passed since the NBA allowed teams to start negotiating contracts with free agents. And all the Mavericks have to show for it is ... rookie free agent Marquis Daniels.

At 6-foot-6, Daniels is a nice fit who adds a big body at the big-point position. But what the Mavericks really need are players such as Alonzo Mourning, Brad Miller, Michael Olowokandi and Rasho Nesterovic -- big and tall free agents who signed with other teams.

Donnie Nelson is trying to figure out why free agents have shunned the Mavs.

"Don't mistake lack of activity for lack of effort," said Nelson, the Mavs' president of basketball operations. "But in order to get, you've got to give."

The Mavericks have been unwilling to part with Dirk Nowitzki, Steve Nash, Michael Finley or Nick Van Exel. That's the group that guided this team to a franchise-record 60 wins and a berth in the Western Conference Finals last season.

"This team has proven results," Nelson said. "This team, if it's kept intact, can do some pretty special things. So the effort is to try to maintain that chemistry and add some key pieces, and that was the thinking behind the whole Alonzo [Mourning] situation. It was, 'Let's keep this team together and add some punch to the front line.' As much as possible, we tried to strive to do that."

With training camp about two months away, the Mavericks will continue to try to fill the physical void at center. One option could be a trade for Warriors center Erick Dampier.