by Tzvi Twersky

Mark Cuban doesn’t need to be worrying about how to best woo LeBron James to Dallas this summer. No. What he needs to be doing is ensuring that his current star player, Dirk Nowitzki, doesn’t skip out of town.

As ESPN.com reports:

The Dallas Mavericks are expecting star forward Dirk Nowitzki to opt out of his contract late next month and become an unrestricted free agent July 1, sources close to the situation told ESPN.com.

The Mavericks, though, continue to negotiate with Nowitzki on an extension in hopes of convincing him to preempt his free agency. They remain confident the leading scorer in franchise history will stay with the only NBA team with which he’s played, even if Nowitzki winds up joining the most anticipated free-agent class in league history.

The sides have until the end of June to reach a deal to keep Nowitzki off the open market, but sources told espn.com this week it’s more likely–with free agency less than 40 days away–the nine-time All-Star becomes an unrestricted free agent for the first time in his career.

“That wouldn’t change our approach one bit,” Mavericks president of basketball operations Donnie Nelson told ESPN.com when asked about the prospect of Nowitzki exercising his opt-out clause.

“We’re going to do everything we possibly can to make sure Dirk is a Maverick for a long, long time,” Nelson added, describing team management as “hopeful, optimistic and expectant” about reaching terms with Nowitzki on a new deal.

Although the opt-out scenario would expose the Mavericks to the possibility of another team swooping in to sign him away, as seen in the summer of 2004 when the Phoenix Sunsstunningly pilfered Steve Nash, numerous executives around the league remain doubtful that they can pry Nowitzki from the grasp of Mark Cuban, given the close bond they’ve forged through Cuban’s 10½-year reign.

“It’s impossible for us to imagine Dirk in any other uniform,” said Nelson, who was instrumental in the pre-Cuban maneuverings on draft day in 1998 that landed Nowitzki and Nash in Dallas in separate trades.

Talk of Dirk opting out first surfaced after the Mavs fell in the first round to the San Antonio Spurs. Add his name to a free agency list that already includes LeBron James, Joe Johnson, Dwyane Wade, Amar’e Stoudemire and Chris Bosh.