Although South Bend, Ind., mayor Pete Buttigieg trails Rep. John Delaney of Maryland by 17 points in an early presidential preference poll in New Hampshire, three Democratic presidential hopefuls are slamming him for not filing the necessary paperwork to get on the ballot, making it harder for him to campaign in the early primary state.

Delaney, Vermont Sen. Bernie Sanders and former Housing and Urban Development Secretary Julián Castro all beat Buttigieg when they were asked who they would support if he doesn't get on the ballot, according to the WMUR poll of more than 700 Granite State voters conducted last week. But Delaney hasn't pursued Buttigieg for the job, telling The Washington Post he would prefer someone who's really competing for the nomination.

Democratic presidential candidate Pete Buttigieg talks to the media in Manchester, N.H., on Nov. 28, 2016.

Buttigieg, in an email statement to the Des Moines Register, disputed the legitimacy of the WMUR poll:

"A string of pseudo-scientific, anonymous online polls have underreported my support for years, and this release is no different," he said. "The New Hampshire Democratic Party is tasked with nominating the party's candidate for president in 2020 and that process has begun."

The state Democratic Party is still sorting out who will be on the ballot, despite previous claims to the contrary. They just put out the ballot last week and so far Buttigieg is not on it.

The ex-Marine and 2009 Rhodes Scholar is in a tight battle with Texas progressive Beto O'Rourke for the title of "charming potential vice president" -- though Buttigieg's foes are not concerned about his job as mayor of the American's second largest city.

The Portland Press Herald reported that Buttigieg isn't registered to vote in Portland.

"It is the dumbest thing I have ever read, because he is the mayor of a city," said one unnamed Democratic operative told the paper. "It's pointless to talk about it."

Democratic presidential candidate Pete Buttigieg, left, talks to reporters following an early voting event at Unity Lutheran Church in New Bedford, Mass., on Feb. 6, 2016.

When the New York Times asked for comment, a New Hampshire Democratic Party spokesman referred to its website, which says "He hasn't filed the appropriate petition to get on the ballot, so he doesn't meet the requirements to get on the ballot. As we head into the final week before the caucus, there will be plenty of time for him to file to get on the ballot. If he does, the New Hampshire Democratic Party and our caucuses go on. If he doesn't, we have no choice but to disqualify him."

Buttigieg is also facing questions on his National Guard service during the Iraq War. He was scheduled to testify before a House Armed Services Committee panel on Thursday, but the hearing was canceled after he violated the terms of his promise by not having his Illinois Superior Court judge say why he failed to notify the committee about military recruiting violations.