Click on the video icon above to hear Sen. Ron Wyden explain his rationale for remaining neutral

EUGENE, Ore. - Sen. Ron Wyden for the first time suggested a timetable on when he would endorse a Democratic candidate for president in an interview Thursday morning.

During an appearance in Eugene stumping for a new version of the G.I. bill, Wyden, one of three undecided Oregon superdelegate, told KVAL he would announce by "the middle of June."

A spokesperson for the senator told The Associated Press Thursday the announcement would be June 13.

"I've been neutral primarily because of the health care legislation," Wyden told KVAL. "I said more than a year ago, we've got the first bi-partisan universal coverage bill now in the Senate, seven Democrats and seven Republiccans, so if I come out for somebody, everybody is going to say this legislation is just a stalking horse for a candidate.

"I never asked to be a superdelegate," he said. "I think that the voters ought to be deciding. I want this done long before the August convention. After the primaries are over I'll be announcing quite quickly."

Wyden was in Eugene Thursday with Rep. Peter DeFazio, D-Springfield, to talk about a new version of the G.I. bill.

Obama has an edge of 7-2 over Hillary Clinton among Oregon's declared supedelegates, with three unannounced. An additional superdelegate will be picked at the state party convention.

Montana and South Dakota hold the nation's last primaries June 3.

Gail Rasmussen became Oregon's third Democratic superdelegate in two days to come out in support of  Barack Obama on Thursday.

Obama beat Hillary Rodham Clinton by 18 percentage points in last week's Oregon primary, and Rasmussen, a member of the Democratic National Committee, cited that win in explaining why she will vote for the Illinois senator at the party's national convention in Denver this summer.

A day before Rasmussen threw her support to Obama, state party Chairwoman Meredith Wood Smith and Democratic National Committeeman Wayne Kinney said they would back him.

Nationally, Obama is fewer than 45 delegates away from the 2,026 needed to capture the party's nomination. With only three primaries left, it looks like the superdelegates - elected and party officials whose picks are not bound by what voters in their home states decided - might push Obama over the threshold.

Other Oregon superdelegates who plan to vote for Obama include U.S. Reps. Earl Blumenauer, David Wu and Peter DeFazio, along with Democratic National Committeewoman Jenny Greenleaf.

Gov. Ted Kulongoski and Rep. Darlene Hooley have endorsed Clinton.

Those who have remained mum about their choice include Wyden, Secretary of State Bill Bradbury and state party Vice Chairman Frank Dixon.

Obama won 31 of Oregon's pledged delegates in the state's May 20 primary, while Clinton won 21. Those delegates are apportioned according to the election results.

Rasmussen, the vice president of the Oregon Education Association, said she will cast her vote for Obama "in honor of the support" he won from the state's voters.