Grossman had said in an interview that he would join John Kerry's (search) team if his boss didn't win on Tuesday.
"I will make it clear that I will do anything and everything I can to help him [Kerry] become the next president, and I will do anything and everything I can to build bridges with the Dean organization," Grossman told The New York Times in an interview published Monday.
"Steve, don't let the door hit you on your way out," Dean campaign spokesman Jay Carson retorted.
Dean confirmed Monday that Grossman is gone from his campaign but wouldn't specify how or why. Dean did say he hasn't talked to him since the article was published. Grossman said he had neither resigned nor been asked to but he understood why Dean considers him no longer part of the campaign.
"I think it's fair to assume my public statements and actions as tantamount to a resignation," said Grossman. "For the record, it didn't happen quite that way. I tried to make it clear I would do nothing prior to the end of the Wisconsin primary."
Asked whether he felt betrayed by Grossman bailing out, Dean said no, adding, "I consider him to be a friend ... we would not have gotten off the ground without his help."
Dean's aides and political advisers had been telling Fox News that without a win Tuesday, his campaign is over and they would pack their bags.
Dean's national campaign manager, Roy Neel, said he thought Grossman would soon join Kerry's campaign.
"He's made clear in his on-the-record comments to the press he has another agenda at work now," Neel said.
"I'm not sure the campaign would turn its back on Steve Grossman but I'm not sure the campaign has had any communication with him," Kerry senior adviser Greg Craig told Fox News on Monday.
When asked whether there's truth to reports that John Edwards' (search) staffers are putting out feelers in Kerry's campaign as well, Craig replied: "Look, these candidates know each other. They served in the Senate together, like each other. They respect the campaigns that they have run. I think they will work well together in the future. That is about all that I can say on that."
This is the second major shake-up in the Dean campaign. After the New Hampshire primary, campaign architect Joe Trippi (search) left after Dean decided to give the top campaign post to Neel, a long-time Al Gore aide.
The so-far winless Dean, meanwhile, insists he's in the race for the long haul although he has no formal post-Wisconsin plan.
"We're going to reassess. We're going to keep going, no matter what, because I think there are a lot of people all over this country who want to rebuild the party and rebuild America in a different way," Dean told Fox News Sunday. "And I think a lot of those people are delegates in New York and Illinois and beyond."
The biggest pressure to pack it in barring a win had been coming from Grossman and Service Employees International Union President Andy Stern.
Sen. Tom Harkin, the powerful Dean-supporting Iowa Democrat, apparently has told the doctor-turned-politician that if he suffers another loss Tuesday and doesn't bow out of the race, the senator will publicly ask Dean to do so.
But Dean has a wild card to play -- a list of Internet e-mail addresses he used to raise $41 million in campaign funds and to boost his campaign's profile last year. The Democratic National Committee is salivating at the thought of getting its hands on this goldmine.
'Not So Fast, John Kerry'
Meanwhile, with a record of 14-2 after weekend wins in Washington, D.C., and Nevada, Democratic front-runner Kerry has assumed the role of presumptive nominee and continued to attack President Bush.
Bush on Monday renewed his demand that Congress extend his tax cuts while Kerry said he agreed on keeping in place two of those tax cuts but said Bush's overall economic policies had failed to create jobs.
"President Bush's failed economic policies have resulted in the loss of 3 million jobs and the biggest surpluses in history turned into the biggest deficits," Kerry said.
Kerry and one-time rival Missouri Rep. Dick Gephardt -- who recently endorsed the front-runner -- on Tuesday will kick off a four-day "jobs tour" of the country to underscore the New Englander's differences with Bush on the economy.
Kerry has yet, however, to establish a full campaign strategy to harness money and volunteers.
Edwards, the senator from North Carolina who so far has only been able to snare a first-place finish in South Carolina, also insisted he's staying in the running.
"Not so fast, John Kerry," Edwards said after his Massachusetts colleague declared he would beat Bush in Sunday night's debate. "We're going to have an election here in Wisconsin this Tuesday. And we've got a whole group of primaries coming up. And I, for one, intend to fight with everything I've got for every one of those votes."
After vying for Wisconsin and its 72 delegates, the remaining candidates will focus on March 2 elections in California, New York, Ohio and seven other states. Edwards hopes Wisconsin voters will bounce Dean from the race.
Edwards aides say they plan to campaign beyond Wisconsin, but they know that if they are not within 5-7 points of Kerry it will be difficult to argue Edwards viability.
For the big races on Super Tuesday -- March 2 -- Edwards is eyeing a win in Georgia and possibly Ohio, as well as a strong showing in upstate New York, which has a strong Republican base. Edwards strategists say they probably will not advertise in California because it is too expensive.
But Edwards advisers have repeatedly told Fox News that "if we get blown out [in Wisconsin] Tuesday we are done."
In Wisconsin, Kerry has 47 percent of the support among likely primary voters, according to a Zogby/MSNBC/Reuters poll released Monday. Dean has the backing of 23 percent while Edwards could grab 20 percent, according to the survey taken Feb. 13-15 of 600 likely voters. Fourteen percent of those polled were undecided.
Kerry said Sunday that he will still "do the work" necessary to win Wisconsin.
"I don't care what the polls say," Kerry told supporters after the Sunday night's debate. "There's only one way to make certain of an outcome in an election. It's get your voters out there, turn out the vote and do the work."
Meanwhile, the candidates seem to be criticizing Bush more than they're taking slaps at each other.
"The principal difference between myself and George Bush is I believe we cannot continue as a divided society," Dean told the Islamic Society of Milwaukee, criticizing the administration for what he called a too-harsh stance against Americans of Arab descent in the wake of the Sept. 11 attacks.
Edwards, meanwhile, picked up a huge endorsement from Wisconsin's largest newspaper, The Milwaukee Journal Sentinel. The paper praised his positive message and noted his pledge to roll back Bush's tax cuts.
On Monday, Edwards sharpened his differences with rivals on trade issues important in the industrial Midwest, particularly the North American Free Trade Agreement, as he flew to four cities Monday.
Edwards insisted there's plenty of time for voters to see those differences and make their pick.
"It's not too late because this primary process is going well into March," said Edwards. "I want voters to know what the differences are between us."
Fox News' Steve Brown, Carl Cameron, Ellen Uchimiya, Kelly Wright and The Associated Press contributed to this report.