PHOENIX, Ariz. - Boston's bulking up.

The Romney headquarter operation will see its staff quadruple in the coming weeks as it shifts into general election mode.

As they transitions from the primary to the general election, Mitt Romney's campaign staff will grow by more than four times - from the current level of 87 to more than 400.

The staff changes were first reported by the New York Times, and later confirmed by ABC News.

Of those coming aboard at Romney headquarters in Boston, Austin Barbour, nephew of former Mississippi Gov. Haley Barbour, who will move to Boston to become the deputy to senior adviser Stuart Stevens.

Additionally, Sarah Pompei, previously the communications director for House GOP Whip Kevin McCarthy, will be joining the communications team, while Richard Grenell, formerly communications director for the U.S. at the UN, will come on to be the national security and foreign policy spokesman.

Lindsay Hayes will up her role on the campaign and become the director of speech writing for Romney. Hayes was former Vice Presidential nominee Sarah Palin's speech writer during the 2008 election. She has held a more informal role on the Romney campaign since November.

These additions to team Romney come after Ed Gillespie, former Republican National Committee chairman, was added as a senior adviser on the campaign earlier this month.

ABC News' Shushannah Walshe contributed to this report.