BOSTON (AP) -- Massachusetts Republicans are scrambling to find a candidate to run for John Kerry's former Senate seat now that would-be GOP front-runner, former Sen. Scott Brown, has opted out of the campaign.

And with the clock already ticking down to the June 25 special election, there isn't a lot of time to rally around a candidate.

Already two potential Republican Senate hopefuls have publicly said they are considering a run -- Wrentham state Rep. Daniel Winslow and Richard Tisei, who narrowly lost a race last year in the state's 6th Congressional District.

Others who have been mentioned as possible candidates include ex-Massachusetts Gov. William Weld, Mitt Romney's former Lt. Gov. Kerry Healey and former Navy SEAL Gabriel Gomez.

Two Democrats have already entered the race, congressmen Edward Markey and Stephen Lynch.