CNN

Barrasso is Wyoming's new senator, effective immediately.

WASHINGTON (CNN) - Wyoming Gov. Dave Freudenthal on Friday named John Barrasso to fill the state's U.S. Senate seat that was held by the late Sen. Craig Thomas.

Barrasso is a two-term Republican member of the Wyoming state Senate and a board certified orthopedic surgeon. Thomas died earlier this month.

Freudenthal, a Democrat, wouldn't divulge why he selected Barrasso over Cheyenne attorney Tom Sansonetti and former state Treasurer Cynthia Lummis - the two other candidates the Wyoming State Republican Party had proposed to fill the vacancy. According to Wyoming elections laws, the vacating senator's state party proposes three candidates to fill the post, one of which the governor must choose.

"There are many factors that went into this decision, and it was the sum of these factors that led me to this choice," he said in a statement. "While I don’t intend to indulge the speculation on why I made this decision, I will say that I hope I made the right choice."

After the state GOP posted an open application for the post on its Web site, 31 people applied for the job.

Barrasso will now serve alongside Wyoming's other Republican senator, Mike Enzi - a man he tried to beat in the 1996 GOP primary to succeed longtime GOP Sen. Alan Simpson.

He will serve as interim senator until January, 2009. A special election in November, 2008 will determine Thomas' permanent successor.

Thomas, diagnosed with Leukemia last November shortly after being elected to a third Senate term, died on June 4.

– CNN Ticker Producer Alexander Mooney