Earlier this week at the Merrill Lynch Media, Communications and Entertainment Conference, SiriusXM CEO Mel Karmazin told investors that he could leave the satcaster at the end of 2012, when his contract is up. By that time, Liberty Media will presumably have a majority stake in the satcaster and control over its fate. Karmazin said that if he was in Liberty's shoes, he might say, "I'm not sure we need Mel." He added, "I am certainly open to having a conversation but certainly my instincts today are that Liberty does not need me at the company."

According to today's New York Post, Karmazin's instincts may be right. Sources tell the paper that when Mel's contract expires at the end of 2012, Liberty will begin a search for a new CEO.

When Liberty surpasses 50 percent ownership, the investment company plans to replace some members of SiriusXM's Board of Directors, according to the Post's sources, as well as Karmazin's comments this week.

Liberty moved a few more percentage points closer to the magic 50 percent number this week, as it filed a SEC filing on Tuesday announcing it now has 49.7 percent of SiriusXM's common shares. As of a week ago, Liberty had 49.3 percent.