When Bobby Brett, his Hall of Fame brother George, and other family members and friends bought Spokane’s minor league baseball team 21 years ago, they had modest goals. They wanted to have fun owning a team, but they didn’t want to lose their shirts doing it. Financial hits were common in the minors.

So, even though the purchase price for the team was a paltry $137,500, they went in as a group of owners to minimize individual risk. “The thought was, let’s buy a team, sell it in a few years, and hopefully we won’t lose too much money,” says Bobby Brett.

Now, the Spokane Indians franchise is worth more than $5 million, according to knowledgeable estimates from other teams. The Indians, an affiliate of the Texas Rangers, usually turns a profit and is tops in attendance in the Class A Northwest League, drawing nearly 183,000 fans last summer.

Since a new generation of owners discovered that small baseball teams could be moneymakers if they were run well and marketed right, minor league ownership has evolved. Teams were once owned primarily by families or small local businesses, often as summer hobbies, but today, some of them have corporations in charge.

“They became real businesses,” says Brett. And the few families that are still involved in minor league ownership increasingly own stakes in several teams. Rare is the traditional mom-and-pop model.

Bob Bavasi, who with his wife co-owned the Everett AquaSox and its predecessor, the Giants, likens the evolution to what happened in the amusement park industry decades earlier. “Back when they were kind of shoddy, backwater parks; before Walt Disney came along and said we could do something like this and make money,” says Bavasi, who’s still involved in the baseball business. He’s also the brother of Mariners General Manager Bill Bavasi.

It didn’t hurt when Major League Baseball began requiring more standardized fields and team facilities for its minor league clubs in 1990. Cities began upgrading stadiums built a half-century earlier, and more fans came. Other cities competed to attract teams with promises of new facilities.

With only so many minor league clubs out there, demand rose, and so did franchise values. And where there’s money to be made, big names rush in. Among the notable owners of minor league teams: Mandalay Sports Entertainment and Comcast Corp., as well as a host of Hall of Fame baseball players.

George Brett, originally part of the ownership group that entered Spokane in the mid-1980s, bought the Class A Tri-City Dust Devils in 2004 for an estimated $2 million. For about twice that amount, the Seattle Mariners-affiliated Everett AquaSox went in 2005 from the hands of a local family to the Carfagna family of Ohio, which owns three minor league teams in as many states. In April, the Carfagnas added former Mariner great Jay Buhner, 2004 gubernatorial candidate Dino Rossi, and several Snohomish County business leaders as minority owners.

Washington’s biggest minor league team, the Tacoma Rainiers, caught the eyes last year of Texas-based Schlegel Sports and pop singer Nick Lachey. Schlegel already owned two minor league hockey teams in the Midwest before closing the deal for the Rainiers, its first venture into baseball, last November. “It’s a very good sport to be in from an economic perspective,” Schlegel Sports President Michael McCall says.

The Rainiers, affiliated with the Seattle Mariners, are the state’s only Class AAA team, drawing 313,031 fans last year. Compare that with 60,000 to 200,000 fans in 2006 for each of Washington’s four Class A teams, which play a shorter summer season.