The Dallas Mavericks have had a relatively stable front office with Mark Cuban as owner. Cuban always seems to add, but rarely subtracts, when it comes to the front office.

In fact, Donnie Nelson — who came to Dallas with his father, Don, in the late 1990s — has served as the team’s president of basketball operations since 2005.

What you may or may not know is that the Mavericks haven’t had a general manager for eight years, which made Nelson the key decision maker when it came to players. That makes the hiring of Houston Rockets executive Gersson Rosas earlier this week rather stunning.

Rosas will be the Mavericks’ new general manager. Rosas will make the personnel decisions moving forward and report to Nelson.

The backstory? When Cuban spoke to the media earlier this week about Rosas, he said he tasked Nelson with finding a new GM a month ago, though Cuban didn’t necessarily call it a “GM.” The Mavs kept this secret for a month with no leaks? Mavs 1, NSA 0.

Cuban said he wanted someone that could help bring the Mavs’ strengths together — Nelson’s international expertise, the team’s expanding analytics department and Cuban’s push for cutting-edge thinking.

Cuban wanted someone who could add their own personnel evaluation skills and project management to the table. Rosas fits the bill.

As a top lieutenant in Houston, Rosas helped rebuild the Rockets and helped them draft key pieces like Chandler Parsons. Other pieces Rosas helped draft were used to make the bold trade last year that brought James Harden to Houston.

And, of course, Rosas likely had some role in luring Dwight Howard. All of these moves have made the Rockets a Western Conference contender.

But the real value here is Rosas’ management of the Rockets’ NBA-D League team, the Rio Grande Valley Vipers. As the Vipers’ GM, Rosas helped them win two D-League titles in the last four years. He’s cultivated a reputation for developing talent that gets promoted to Houston, or is signed away by other NBA teams.

This is the same approach the Dallas Stars took in hiring general manager Jim Nill. Nill’s reputation was in player development and his excellent management of the Detroit Red Wings’ top minor-league affiliate was a factor in the Stars’ decision-making.

No doubt that’s part of the reason the Mavericks went after Rosas.

While the Mavericks have been a great team the past decade, they’ve done it with free agency. Their record in the NBA Draft the past dozen years is woeful. They’ve traded many of their picks away, and what picks they’ve taken have rarely panned out.

Remember Josh Howard? He was their best selection during that time frame. You can throw Devin Harris in there, but the Mavs gave up on both guys.

The Mavericks haven’t developed players internally in the way that the San Antonio Spurs and the Oklahoma City Thunder have done. In fact, the Thunder plundered the Spurs’ front office to hire GM Sam Presti, and the Thunder went to the NBA Finals last year. Those two teams are the gold standard for player development in the NBA. The Rockets are getting there.

The new Collective Bargaining Agreement makes it nearly impossible for Cuban to outspend other teams. The luxury tax hit is too cost-prohibitive now. He’s failed in the past two seasons in luring a top free agent to Dallas because, beyond Dirk Nowitzki, the Mavs don’t have any key pieces to build around. They’re not an attractive team.

Those two forces have combined to force Cuban and Nelson to change tactics. The same thing happened in the Texas Rangers front office in 2007. Free agency wasn’t working for the Rangers and they chose the path of player development. Half-a dozen years later the Rangers had made two World Series appearances.

Hiring Rosas represents a sea change in the way the Mavs will do business moving forward and is an acknowledgment from Cuban that he, for once, is behind the times.

Rosas has helped build the Houston Rockets into a talented team by luring players like James Harden.

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Rosas has helped build the Houston Rockets into a talented team by luring players like James Harden.