(CNN) -

Mary Burke, Wisconsin's Democratic nominee for governor, will not appear in public with Barack Obama when the President travels to Milwaukee on Monday to mark Labor Day in the key 2014 battleground state.

The President and Burke are both scheduled to attend Milwaukee's annual "Laborfest" celebration, a gathering of union activists that play a critical organizing role in Democratic politics.

"Mary Burke has been scheduled to attend Laborfest in Milwaukee for weeks," Burke communications director Joe Zepecki told CNN in a written statement. But because "the President's Monday visit to Milwaukee is for an official White House event and not a campaign event, her participation in the public portion of events would not be appropriate."

Zepecki noted, however, that Burke will meet privately with Obama during the President's visit, and "hopes to have him back in Wisconsin for a campaign event before Election Day."

Obama's Labor Day stop has been widely publicized by Milwaukee Mayor Tom Barrett.

The President's appearance with the Democratic gubernatorial nominee is notable in light of the fact that Burke also declined to appear with Obama the last time the President traveled to Wisconsin. With Obama's approval ratings sagging, his value to other Democrats on the campaign trail in swing states this year has been called into question.

The President does, however, continue to play a vital fundraising role for Democratic candidates nationwide.

Walker's campaign press secretary Alleigh Marré said "Burke can offer up excuses and try to hide from President Obama and his rotten approval ratings, but she can't hide from the fact that her and the president's failed economic policies are one and the same."

Burke is currently locked in a tight race with incumbent Republican Gov. Scott Walker. Forty-nine percent of likely voters support Burke compared to 47% for Walker, according to an August 21-24 Marquette Law School poll. The survey has a sampling error of plus or minus four percentage points, which means the two candidates are locked in a statistical dead heat.

"I've known from the start that this is going to be a really tough race," Burke told CNN affiliate WTMJ. "The numbers are improving slightly among likely voters, and that was good to see. It confirms what I hear as travel around the state."

Walker, a conservative star and potential 2016 White House contender if he wins re-election this year, has been fending off allegations of wrongdoing throughout most of his term.

While the Marquette poll was in the field, new revelations emerged that Walker may have illegally coordinated with outside groups in a 2012 Democratic-led attempt to recall him from office.