New Mexico Democrat Terry Brunner, a longtime state director for Sen. Jeff Bingaman (D-N.M.), is weighing a run for the seat being vacated by his former boss. 

According to a Democratic source in the state, Brunner spoke with New Mexico party officials in recent weeks about a potential run in the event of a Bingaman retirement.  

Reached by email Friday, Brunner confirmed that he was weighing a run for the seat, saying he intends to make a decision "in the next few weeks." 

Brunner left Bingaman's office in 2009 after he was named state rural development director at the USDA by President Obama. Brunner ran Bingaman's 2006 reelection campaign and served as a senior adviser to Obama's 2008 campaign in New Mexico.  

Brunner joins the list of other potential Democratic candidates for the seat, which includes Reps. Martin Heinrich (D-N.M.) and Ben Lujan (D-N.M.), as well as former Lt. Gov. Diane Denish (D).  

Bingaman announced his retirement Friday, telling supporters at an event in New Mexico that this year was the "right time for me to step aside and allow someone else to serve." 

An open seat contest offers the GOP a better pick up opportunity next year, but Democrats are already expressing confidence that they'll hang onto Bingaman's seat. 

A Democratic source pointed to polling Friday that showed Heinrich besting two rumored GOP Senate contenders -- Rep. Steve Pearce (R-N.M.) and former Rep. Heather Wilson (R-N.M.).

One Republican who would make a race against Heinrich much more interesting, according to a recent survey from Democratic-leaning Public Policy Polling, is former New Mexico Gov. Gary Johnson, who is weighing a 2012 presidential bid. 

Asked about numbers that showed him running well in an open seat Senate race at last week's Conservative Political Action Conference, Johnson called the poll "cool," but poured cold water on the notion of a Senate bid. 

"No way," Johnson told The Ballot Box of a 2012 Senate bid. "I'd be terrible at the job. Being in the Senate is all about bellying up to the trough, which is not what I do."

-Updated and corrected at 7:21 p.m.