Rep. Charles Boustany (R-La.) announced Monday that he will not run for Senate in 2014.

Rep. Charles Boustany (R-La.). (J. Scott Applewhite, File/Associated Press)

Boustany, the second-longest serving member of the state's congressional delegation, would have been formidable had he run. His name was floated just a couple weeks ago as a potential entrant to what is expected to be a crowded field against Sen. Mary Landrieu (D-La.).

But Boustany's spokesman said Monday that he wants to remain focused on his work in the House.

“Serving on the House Ways and Means Committee allows Congressman Boustany to focus on issues important to Louisiana ranging from trade, to comprehensive tax reform, to health care. He looks forward to continue representing South Louisiana on Capitol Hill," said the spokesman, Neal Patel.

Rep. Bill Cassidy is expected to be a frontrunner for the seat, and other potential GOP candidates include Lt. Gov. Jay Dardenne, Rep. John Fleming and former congressman Jeff Landry. Boustany easily dispatched Landry in a runoff this year after the two men had their districts combined in redistricting.

Landrieu is considered one of the most vulnerable incumbents in the country and has made clear she will seek another term in 2014.