While Democrats frantically try to block Scott Brown from going back to the U.S. Senate, there are also increasing fears he could pose an even bigger threat as the next Massachusetts governor.

Republicans close to the departing U.S. senator said he’s itching to go back to Washington to replace John Kerry, but Democrats are buzzing more about a potential Brown gubernatorial campaign in 2014. It may be tempting for Brown to run in a special election against a vulnerable Rep. Edward J. Markey, but he should reject the easy play and go for the job that really matters — running the state of Massachusetts.

“In the last week, there has been more speculation (about a Brown gubernatorial campaign),” one top Democratic strategist said. “He’d have a much better shot at (governor).”

Brown could beat Markey, but it’s interesting that he has had little to say about the Malden Democrat since Markey announced his intentions to run for Senate. That could mean Brown is still undecided, according to some Democrats.

Brown knows Democrats will throw millions of dollars against him and use the same strategy they used last year for U.S. Sen.-elect Elizabeth Warren, trying to tie him to national Republicans. It’s a winnable race for Brown but by no means an easy one, and a second Senate loss in six months would essentially end his once-promising political career.

It would be much more devastating to Democrats if a Republican such as Brown were to take over the Corner Office, and that’s what has party leaders most concerned.

And Brown’s prospects of getting elected governor look to be much brighter than in another Senate race later this year. By 2014, Democrats also will be seriously weakened by a series of scandals and screwups under Gov. Deval Patrick, with several Democratic top lawmakers tainted or even on trial in the Probation Department patronage affair.

Brown would be a perfect choice to clean up Beacon Hill and get Democrats and Republicans to actually work together — much the way former Gov. William Weld and even former Gov. Mitt Romney did.

Brown confidants say they still expect him to announce his Senate campaign once Kerry is confirmed.

“If he chooses to run again for U.S. Senate, and I think he will, he will be a formidable candidate,” said state Rep. Dan Winslow (R-Norfolk), a close Brown friend.

But if you were Scott Brown, who would you rather run against, Ed Markey and the entire Democratic Party, or state Treasurer Steve Grossman or Attorney General Martha Coakley?

That’s the question Brown has to answer in the next few weeks.