Mark Critz, the district director for the late Rep. John Murtha (D-Pa.), is poised to enter the race to succeed his boss.

“Yes, I am running to be the next Congressman representing the 12th district of Pennsylvania. And I need your vote. And I need your support,” Critz says in a voice mail greeting on his personal cell phone.

Critz resigned his position Monday in preparation for a bid. In an e-mail announcing his resignation obtained by Roll Call, he wrote that he will make his announcement Monday or Tuesday.

Critz’s move comes on the same day the Congressman’s widow, Joyce Murtha, is expected to announce that she is not going to run for her late husband’s seat. Critz did not immediately return a request for comment, but at least one local Pennsylvania source said it’s highly likely that Joyce Murtha will endorse Critz’s candidacy.

In addition to Critz, two top-tier Democrats have already announced their bids for the seat: Former Lt. Gov. Mark Singel, who got into the race this weekend, and former state Treasurer Barbara Hafer, who entered the race last week.

There are a handful of other Democrats weighing the race, but Singel and Hafer are the early frontrunners. Cambria County Controller Ed Cernic Jr. is expected to announce Monday that he’s running, and conservative former Cambria County Controller Albert Penksa is considering a bid. Navy veteran Ryan Bucchianeri (D) has been in the race for several months.

Local officials are expected to confirm a special election calender by Wednesday, according to a Democratic source familiar with the arrangement. The expected calendar, however, will require candidates to submit their names by March 3, while the party will hold a convention to pick their nominee on March 6. The state Democratic Party executive committee could confirm their pick by March 8 — one day before the statewide filing deadline to run for a full term.

Murtha died Feb. 8 from complications following gallbladder surgery.

The special election is scheduled for May 18, although it’s unclear whether national Republicans will target the race.

Two Republicans have already announced their candidacies, 2008 GOP nominee Bill Russell and businessman Tim Burns, and local party officials will pick their nominee in Latrobe, Pa., for the special election on a yet-to-be-determined date.