DALLAS - Once again, draft night is shaping up as a prelude to free agency for the Mavericks.

Dallas has the 21st pick in the second round Thursday night, and three openings in the starting lineup after finding out for sure on the eve of the draft that guard Monta Ellis will opt out of the final year of his contract and become a free agent.

President of basketball operations Donnie Nelson doesn't figure to find a cornerstone late in the first round and says Dallas' needs are widespread enough that the "best player" approach will apply.

Nelson will assuredly be busier than a year ago, when a pre-draft trade with the New York Knicks for Tyson Chandler left the Mavericks without a pick. This year's draft could be more like 2013, when Dallas traded down while counting pennies under the salary cap before the unsuccessful pursuit of Dwight Howard in free agency.

"We'll be active like we are every draft," Nelson said this week. "I can't tell you if we're going to keep it or if it makes more sense for us to trade out for a more established player."

The more likely road to yet another rebuilding of the roster is through free agency, with All-Star forward LaMarcus Aldridge and center DeAndre Jordan the top targets. Aldridge is from the Dallas area, and Jordan grew up in Houston.

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Either way, the Mavericks will need point guards after failing to win a playoff series for the fourth straight season since winning their first championship.

Rajon Rondo won't return after a failed trade with Boston last season, and J.J. Barea is a free agent Dallas would like to re-sign. Devin Harris is on the roster, and the draft could provide help, with Duke's Tyus Jones projected in that area after turning pro as a freshman.

"If you had to guess, there will probably be more high-quality point guards there at 21 than any other position," Nelson said.

Things to consider heading into draft night for the Mavericks, who also have the 52nd overall pick in the second round:

PRELUDE TO A MISS? Since finding a starter late in the first round is unlikely, the story for the Mavs will quickly turn to the pursuit of Aldridge and Jordan starting July 1. Dallas has whiffed on several big-name free agents since choosing salary cap flexibility over keeping the title team together in 2011. And the Mavericks are running out of time to build a contender for Dirk Nowitzki, who just turned 37 and is going into his 18th season.

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DRAFT PIECES: Dallas used a couple of recent draft picks in the two big trades of the past year. Shane Larkin (No. 18 in 2013) went to New York in the Chandler deal, and Jae Crowder (34th overall in second round in 2012) went to Boston in the Rondo trade. Chandler is joining Rondo on the open market this year.

VACANT BACKCOURT: While Harris is under contract, the losses of Rondo and Ellis leave big ball-handling and scoring voids. Ellis (18.9 points per game) was the first player other than Nowitzki to lead Dallas in scoring since 2000. The big German's days as the go-to scorer are dwindling.

DON'T FORGET ABOUT PARSONS: Chandler Parsons is coming off knee surgery that could limit his availability through training camp and the early part of the season, but the Mavericks have to find partners that mesh with the 26-year-old forward since they owe him about $31 million over the next two seasons.

DEEP ENOUGH: Nelson says the draft runs about 24 players deep before projections fall off significantly, which means the Mavericks should have a chance to find a contributor if they hang on to their pick.