Republican state Rep. Daniel Winslow says he's ``99 percent'' sure he'll run in a special election for the U.S. Senate seat formerly held by U.S. Secretary of State John Kerry.

Winslow formed an exploratory committee on Tuesday to test the waters for a possible candidacy. He would not say how long he would take before making a final decision on entering the race, telling reporters he needed more time to assemble a campaign team, talk to potential donors and take other steps.

The Norfolk Republican is a former judge who served as chief legal counsel during the administration of former Gov. Mitt Romney.

Former U.S. Sen. Scott Brown and several other Republicans have announced they will not run in the special election, scheduled for June 25. [Associated Press]