The chairman of the Democratic Governors Association (DGA), Montana Gov. Brian Schweitzer, will endorse former Democratic National Committee (DNC) Chairman Terry McAuliffe in Virginia's gubernatorial primary next week, a Democratic source confirmed Thursday.

Schweitzer's backing was first reported by the Virginia-based blog Not Larry Sabato in mid-May, and the Washington Post reported it Thursday.

The Post said Schweitzer would campaign with McAuliffe on Friday, officially endorsing him in Arlington, right across the border from Washington, D.C.

Schweitzer's endorsement is a person one and not in his capacity as chairman of the DGA, but it will be viewed as a nod from the national party to McAuliffe's candidacy.

McAuliffe's fundraising presence would be a major boon for national Democrats, who would rather not have to prop up their nominee after what has turned out to be a bruising and expensive Democratic primary. The winner gets state Attorney General Bob McDonnell, who had no GOP primary opponent.

Recent polling has shown McAuliffe losing his lead over state Sen. Creigh Deeds and former state Del. Brian Moran, and the late endorsement is a sign of just how in-jeopardy McAuliffe's lead is.

It is worth noting that the most recent polling shows that two in 10 voters are still undecided.