(CNN) -- Get ready Massachusetts: Another special election to fill a U.S. Senate seat may be coming your way. And jockeying is already underway among potential candidates, even before it's official there will actually be vacant seat and an election.With U.S Ambassador to the U.N. Susan Rice no longer in contention to succeed Secretary of State Hillary Clinton as America's top diplomat, Senate Foreign Relations Committee Chairman John Kerry, always one of the top contenders for the job, now becomes the odds-on favorite to be nominated by President Barack Obama.
And that means the five-term senator from Massachusetts and 2004 Democratic presidential nominee would step down from his job, leaving a vacant seat in the Bay State and triggering a special election as early as May or June of next year.
Here's how it could work. If nominated by the president and confirmed by his colleagues in the Senate, Kerry would leave Congress, and Deval Patrick, the state's Democratic governor, would appoint a replacement to fill the seat.
By state law, a special general election is required to take place 145 to 160 days after a vacancy occurs. So if Kerry were nominated, confirmed, and then stepped down on January 21 (Inauguration day), the election would take place between June 14-29, with primary elections being held six weeks earlier.
Whoever wins the special election would serve the final year and a half of Kerry's term and would then be able to run again for a full six-year term in office in the 2014 midterm elections.
The big question is whether Patrick will appoint someone to serve as an interim senator or name someone who would run in the special election and possibly clear the primary field.
In 2009, after the death of longtime Democratic Sen. Ted Kennedy, the governor said he would only appoint a caretaker and named former Democratic Party chairman Paul Kirk to fill the seat. Later that year, state Attorney General Martha Coakley won a multi-candidate primary but was upset in the January 2010 general election by onetime long shot Scott Brown, a Republican state lawmaker.
Patrick says it's too soon to say if he'll once again name a caretaker or appoint someone who would run in the special election. But a Democratic strategist in Massachusetts says Patrick is under pressure to avoid naming a caretaker, in the hopes of preventing a divisive primary.
"It didn't work out too well last time with a caretaker being named," said the strategist, who asked to remain anonymous in order to speak freely.
The strategist told CNN that both Rep. Ed Markey and Rep. Michael Capuano have already separately met with Patrick to ask for the appointment, if Kerry's seat does open up.
Markey, who's served 19 terms, is the dean of the Massachusetts House delegation. He didn't run in the special election two years ago to replace Kennedy because at the time the Democrats held the majority in the House and Markey was chairman of the powerful Energy and Commerce Committee.
Capuano, who's served seven terms, last month told CNN affiliate WCVB that "I will consider it," when asked if he'd run in a special election. Capuano ran in the special election two years ago, finishing second in the Democratic primary to Coakley.
Democratic sources say State Treasurer Steve Grossman also has interest in the Senate seat, if it opens up. And other Democrat mentioned in media reports is Rep. Stephen Lynch, a social-conservative from South Boston.
Another name that was mentioned in the last special election, and that's come up again, is Vicki Kennedy. A source with knowledge of the conversation tells CNN that the governor met with Kennedy, the widow of the late senator, in person to talk about the possibility of Kennedy filling Kerry's seat if he's nominated for secretary of state. The source has no other details about when, where, or the specifics about the conversation.
It's not clear if Kennedy would serve in the caretaker role or if she would run in the special election. In the past Kennedy's said she would be unlikely to accept such an appointment. ABC's Jonathan Karl was first to report Kennedy's conversation with the governor.
There's also some speculation that Patrick himself would have interest in the Senate seat. But last month the governor pushed back at such speculation, saying "No, no. I have the only job in politics that I've ever wanted," and added that "I have two more years to finish it up. We've got a lot to do."
On the Republican side, most speculation focuses on Sen. Brown, who was defeated last month by Democratic challenger Elizabeth Warren. In his Election night concession speech Brown said "defeat is only temporary."
And in his Senate farewell speech Thursday, Scott repeated that line, and also added that "depending on what happens, and where we go, all of us, we may obviously meet again, but I'm looking forward to continuing on with those friendships, with continuing on working with my staff."
If he runs, Brown would be viewed as a strong contender.
Brown won the January 2010 special election by five points over Coakley, but lost to Warren by eight points in his re-election bid last month. Around 2.3 million voters cast ballots in the 2010 special election, and nearly 3.2 million voting in last month's general election.
Republicans often perform better in special elections, which usually draw far fewer voters than regularly scheduled elections. But a Democratic party source tells CNN that a special election in 2013 "would not be a repeat of 2010," when many Democrats took the race for granted, in a state where Democratic voters greatly outnumber Republican voters.
"We see what happens when Democrats are committed to getting out the votes," said the source, as he pointed to Brown's eight-point loss to Warren last month. The big question is whether the 2013 electorate will look more like that of the 2010 contest or that of last month's general election.
One other GOP name that's been mentioned in a few media reports is former Massachusetts Gov. William Weld, who recently moved back to Massachusetts from New York.
But a Republican strategist in Massachusetts discounts such talk, telling CNN that "the only thing predictable about Bill Weld is his unpredictability, but for now it looks like he has his feet firmly planted in the concrete of the private sector."
CNN Chief National Correspondent John King and CNN Anchor John Berman contributed to this story.