Updated

Former Vice President Walter Mondale will agree to replace the late Sen. Paul Wellstone on the Minnesota Democratic ticket in a race that could determine control of the U.S. Senate, Fox News has learned.

Wellstone's eldest son, David, personally made the request at a meeting Saturday at Mondale's law office, said Mike Erlandson, chairman of the state's Democratic-Farmer Labor Party.

Video: Feds Investigate Cause of Wellstone Crash

Erlandson, who knew of but was not present at the Saturday meeting with Mondale, planned to call a meeting Wednesday of the party's state central committee to nominate a ballot replacement for Wellstone. He said the family blessing makes Mondale the clear favorite.

"He is certainly the public sentiment front-runner, among activists, among party leadership," Erlandson said. "We've had hundreds of phone calls and emails."

Mondale, 74, has not commented publicly on his interest and those close to him don't expect him to until after Tuesday's memorial service for Wellstone, who was killed Friday in a plane crash in northern Minnesota.

Mondale didn't return calls Sunday for comment.

Republican officials, however, are already fashioning a message with the presumption that Mondale will enter the race against former St. Paul Mayor Norm Coleman.

"The voters will have a decision between the past and the future," said Bill Walsh, a state GOP spokesman. "Walter Mondale is clearly the past."

National Democratic leaders have also made it clear that Mondale is the favored choice.

A Democratic source, speaking on condition of anonymity, said Saturday that Senate Majority Leader Tom Daschle and Sen. Patty Murray, the head of the party's campaign committee, had reached out to the former vice president. Additionally, Democratic sources said, prominent labor leaders have expressed an interest in Mondale.

Daschle said Mondale was clearly the strongest possibility, calling him "the great unifier" and predicting overwhelming popular support if Mondale runs.

"I know Paul would want us to win that election, and we're guaranteed that we're going to do all we can to make that happen a week from Tuesday," Daschle said on CBS's Face the Nation.

Meanwhile, near Eveleth, Minn., victims' relatives were expected to visit the site of the plane crash for a private memorial service Sunday. Wellstone, his wife, Sheila, daughter, Marcia, three campaign workers and two pilots died in the crash. The cause of the crash, which happened in freezing rain, remains under investigation.

Wellstone, a 58-year-old liberal, died in the final days of a tough race for a third term.

The race was one of a half-dozen or so expected to determine which party will control the Senate next year. The loss of Wellstone leaves the chamber split 49-49 among Republicans and Democrats, with one Independent, Jim Jeffords of Vermont, who is allied with the Democrats.

The list of potential replacements for Wellstone on the ballot has included several politicians one generation younger than Mondale, including Mondale's son, Ted, and Skip Humphrey, the son of another former vice president. Also mentioned was Alan Page, a state Supreme Court justice and a former Minnesota Vikings star. He showed no interest in a U.S. Senate campaign when he was approached two years ago.

While Democrats considered whose name would go on the ballot, Gov. Jesse Ventura met with legal advisers Saturday to discuss appointing a temporary replacement for the remaining months of Wellstone's term.

Ventura said if he names someone, it probably will be a Democrat because it's "only fair."

He also said he would favor someone who doesn't plan to run for the office.

It appeared it wouldn't be legal to leave Wellstone's name on the ballot. Absentee ballots already marked for Wellstone won't count for the Senate race, but people who submitted them could go to the polls on Nov. 5 and submit a new ballot.

Two years ago, when Missouri Gov. Mel Carnahan was killed in a plane crash three weeks before the election while running for the Senate, his name remained on the ballot and he beat Republican Sen. John Ashcroft. Carnahan's widow, Jean, was appointed to serve in his place and is now seeking election.

Under Minnesota law, a death creates a vacancy on a ballot. The candidate's party can nominate someone to fill that spot, but that candidate would have to fulfill certain requirements, including being alive, Attorney General Mike Hatch said.

The Associated Press contributed to this report.