Updated

Former Vice President Joe Biden has canceled his plans to attend Democrat Day at the Illinois State Fair this week because he's "under doctor's orders" to limit his travel, state Democrats said Tuesday.

Biden, 75, was scheduled to be the keynote speaker Thursday to boost J.B. Pritzker, a Democratic gubernatorial candidate, the Chicago Sun-Times reported.

“Everyone who knows Vice President Biden knows that he gives our party and our country his all, but unfortunately he is sick and is under doctor’s orders not to travel."

— Doug House, President of the Illinois Democratic County Chair's Association

“Everyone who knows Vice President Biden knows that he gives our party and our country his all, but unfortunately he is sick and is under doctor’s orders not to travel," Doug House, president of the Illinois Democratic County Chair's Association, said in a statement, according to CapitolFax.com.

The presence of Biden, considered a possible 2020 presidential contender, "will be noticeable at Thursday's event," the Sun-Times reported.

"The cancellation is of course disappointing, but it is clear that the circumstances are simply unavoidable," House said. "We all hope he gets well soon and I’m sure he’ll be back campaigning for Democrats in Illinois and across the country in no time."

Demand for the event was so high that 2,500 tickets for the event in the hotel's main-floor ballroom sold out the first week and room for an additional 700 people was created on the hotel's second floor, Springfield's State Journal-Register reported.

The event is held in Springfield, Ill., and will continue despite Biden's absence.

Pritzker is taking on Republican incumbent Bruce Rauner, Conservative Party candidate Sam McCann (a state senator) and Libertarian Party candidate Kash Jackson in the Nov. 6 election. The Illinois primaries were held March 20.