(CNN) - Massachusetts Rep. Michael Capuano is taking the initial steps to run for the vacant Senate seat long held by Ted Kennedy - making him the third Democrat likely to jump into the closely-watched race.
In a statement released Tuesday, Capuano said he has obtained the necessary paperwork to run for the seat because his positions most "closely mirror" those of the late Massachusetts senator.
"I believe that the voters of Massachusetts want to continue the progressive ideals that Senator Ted Kennedy fought for during his decades of service," Capuano said. "No other candidate being mentioned or already announced more closely mirrors Ted Kennedy's positions on important issues of war and peace."
The move comes nearly a week after state Attorney Gen. Martha Coakley formally announced her Senate bid. Massachusetts Rep. Stephen Lynch also appears poised to enter the race, obtaining nomination papers Friday.
Capuano's decision also come a day after former Rep. Joseph Kennedy, the nephew of Ted Kennedy who was widely viewed as a favorite for the seat, announced he would not run.
Another possible contender, former Rep. Marty Meehan, told Boston radio station WBZ he will not seek the seat. Meehan is now chancellor of the University of Massachusetts-Lowell.
Capuano's district represents parts of Boston and its immediate suburbs.
The Democratic primary for the Senate nomination is scheduled for December 8. The special election to fill the seat is scheduled for January 19, 2010.