Brown's decision not to run again surprised many Massachusetts Republicans, who considered him their best chance at taking the seat vacated by now Secretary of State John KerryJohn Forbes KerryPrimary care is a home run for both sides of the aisle Mellman: Memories may be beautiful, yet… Lieberman: Senate should fulfill constitutional duty, confirm Mike Pompeo MORE.

The party now has the unenviable task of recruiting a candidate to run in a special election in a state President Obama won by more than 20 points.

While Hughes admitted in her email Brown's decision not to run is "certainly a disappointment for many in our party," she also expressed optimism for the party's potential in the race.

"Some cynics in the media may try to portray this as a negative. However, if we all work together, we can seize the opportunity that this presents," she wrote.

A handful of possible contenders, including former Gov. Bill Weld and local businessman Gabriel Gomez, have emerged since Brown announced his decision.

Hughes also emphasized the need to "unite behind our eventual nominee" in the race, but framed the upcoming special election as preparation for 2014.

"Our collective efforts this year will set the stage for 2014 when our goal must be to recapture the Governor’s Office and add seats in the state Legislature and Congress," she wrote.