Apparently, Tom Hicks (rangers owner) is having money troubles.

Hicks owns the Rangers, the Dallas Stars, and has defaulted on $525M in loans.

Creditors to Texas financier Tom Hicks's Hicks Sports Group have declared the company in default, a measure that could eventually dislodge the Texas Rangers baseball club and Dallas Stars hockey franchise from his control.

Additionally, the NYT adds:

The Rangers baseball team and the Stars hockey team are now unable to pay both their operating expenses and their debt service, the newspaper said.

As for whether the team might be sold:

Major League Baseball's rules for such situations are more fluid, though if Hicks Sports Group can't satisfy lenders, the lenders can eventually force an MLB-sanctioned sale of the Rangers.

Hicks, on the other hand thinks he won't have to sell the teams:

"I'm confident that I'll be able to reach agreement with 51% of the lenders because I will be able to fund all the cash needs of the two teams during the period that I'm bringing in new partners, which will help us to drastically reduce if not eliminate HSG's debt,"