Updated 7:35 p.m. Dec. 15 | Sen. John Kerry, D-Mass., is set to be nominated as the next secretary of State, according to news reports Saturday evening.

It became clear in the wake of Susan Rice’s withdrawal from consideration on Thursday that Kerry was the leading contender for the position, touching off a theoretical chess game of speculation about who will fill his Senate seat.

If Kerry resigns to move to the State Department, Gov. Deval Patrick (D) will appoint a short-term successor to serve until a special election can take place. More on the politics of that after the jump, but first, here are the names being mentioned for a special election.

DEMOCRATS:

One plugged-in state Democratic operative laid out the different categories for possible Democratic candidates.

Group One — Current House Delegation 

A 2013 special election would essentially be a free run for any House member because he or she wouldn’t have to give up his or her current seat. Here are the names being floated around Boston on Friday morning. Also, if it is a Member of Congress who succeeds Kerry either by appointment or election, the same succession laws apply to that House seat as a Senate vacancy.

• Rep. Edward J. Markey: “I heard that Markey is trying to clear the field. Good luck,” the operative said.
• Rep. Michael E. Capuano: He ended up being the only member to run in the Senate special election that resulted from the death of Sen. Edward M. Kennedy. He finished second in the primary and is viewed as almost certain to run again if there is a vacancy.
• Rep. Stephen F. Lynch: He eyed running in the 2010 special election but opted against it.
  

Group Two — Also-Rans From 2012 Democratic Primary  

Sen.-elect Elizabeth Warren essentially cleared the Democratic field last cycle. Some Democrats who tried to run last time could try again:

• Newton Mayor Setti Warren
• City Year co-founder Alan Khazei
• Immigration attorney Marisa DeFranco
• Activist Bob Massie

Group Three — Fresh Face 

• State Sen. Benjamin Downing

REPUBLICANS: 

• Sen. Scott P. Brown: Brown is the most obvious GOP candidate, and if he runs, he will clear the field of mainstream candidates. But the 2014 gubernatorial race weighs as an option for Brown as well. Democrats are preparing for him to run again.
• Former Gov. William Weld: Operatives on both sides have noted that Weld recently moved back to the state and subsequently made the rounds at newspaper editorial boards and in local television interviews.
• Former GOP gubernatorial nominee Charlie Baker: His name is being mentioned, but some view him as more likely to run for governor. Baker is a Weld disciple.

Both sides say a wealthy businessman could jump into the race in either party.

The local ABC affiliate reports that Patrick has reached out to Vicki Kennedy, the widow of the late senator, about being his appointed selection. The news report added that sources close to Kennedy told ABC it was unlikely she would accept the appointment. A Boston Democratic operative concurred that a Vicki Kennedy appointment or campaign was highly unlikely.

In 2009, Patrick appointed a Democratic caretaker, Paul Kirk, to serve in the interim between Kennedy’s passing and the January 2010 special election. Patrick kept the option open to appoint a senator who could run in the special election as well on WCVB Thursday night.

Massachusetts law dictates that a special election must take place between 145 and 160 days after the vacancy is created — around five months. That would put a special election sometime in May or June, depending on when and if Kerry files his letter of resignation. The winner of that special election will hold the seat for the remainder of Kerry’s term, which runs through 2014.

Local speculation about filling a possible Senate vacancy began almost as soon as President Barack Obama was re-elected. The Springfield Republican reported in November that Patrick expressed distaste for the law that allows the special election rather than an appointment to hold the seat for the remainder of the term. But state house Democrats were not enthused about changing the law in late November, according to WWLP. State Democrats changed the law in 2004, when Kerry was running for president, to allow for a special election. The reason? They wanted to strip former GOP Gov. Mitt Romney from the ability to make a long term Senate appointment.