Sirius XM Radio

(SIRI) - Get Report

is seeking an investment from

Liberty Media

(LINTA)

, the

Wall Street Journal

reports, in a last-ditch effort to fend off an unsolicited takeover approach from satellite entrepreneur Charles Ergen.

The talks set the stage for a battle between the Liberty-controlled

DirectTV

(DTV)

and Ergen's Dish Network for control of the country's sole satellite-radio operator.

Liberty, controlled by billionaire John Malone, emerged as a potential "white knight" for Sirius after Ergen made an unsolicited offer in late 2008 to take control of the radio operator, according to the newspaper.

Though the talks between Sirius and Liberty are advanced, a deal remains far from certain, the

Journal

reports, citing a person familiar with the matter. It wasn't clear how much Liberty would be willing to invest in Sirius and whether it would end up with control.

Ergen, who controls a satellite empire around

EchoStar

(SATS) - Get Report

and Dish, quietly began amassing Sirius debt in the fall. He is now using that debt, including about $175 million in bonds that mature on Feb. 17, as leverage to try to force Sirius into a deal. Sirius, which carries a total debt load of about $3.25 billion, is nearly out of cash and will likely be forced into bankruptcy proceedings or a deal with Ergen if the company can't secure funds to repay its obligations by Tuesday, the

Journal

reports.

Ergen has offered to inject about $500 million into Sirius and restructure the roughly $375 million in short-term debt he holds in return for control of the company. Sirius rejected the offer.

This article was written by a staff member of TheStreet.com.