"I think that there's a healthy discussion going on within the Democratic Party," Pritzker said. "We tolerate dissent, and we think it's good for democracy to have this conversation. And, you know, for, for me anyway, my word is my bond. You know, I honor my commitments. Joe Biden is going to be our nominee, unless he decides otherwise."
The president has been facing mounting pressure and questions over whether he should go on with his campaign.
Pritzker is among many Democratic stalwarts whose names have been floated as possible replacements.
In sticking with Biden, the governor put a different frame on the race.
"Unless he makes a different decision, I'm on board and I'm supporting the president. Again, he's been good for the country. And remember what the contrast is. This is a, you know, a despotic narcissist on the other side of Donald Trump and the Supreme Court just gave him even more power potentially, with immunity from prosecution for things that I think we all know he's capable of doing," Pritzker said.
Meanwhile, Illinois Congressman Mike Quigley has become the latest prominent Democrat to question Biden's suitability.
Rep. concerned over down-ballot election impact if Biden stays in race
A growing number of Democrats across the country are publicly raising concerns about whether the president should continue his campaign.
A Democratic representative from Texas has now publicly called for Biden to step aside.
Quigley, D-Chicago, did not go that far. But, after the president's debate performance, Quigley is concerned about the down-ballot impact if Biden stays in the race.
"This was a horrible debate. I think we need to be honest about that," Quigley said.
Could Pritzker replace Biden on presidential ticket?
Quigley echoed a sentiment shared by many Democrats.
But his concern is that if Biden stays in the race, it might affect other Democrats on the ballot across the country.
"In whatever decision he alone can make, he has to understand and appreciate that decision won't just affect who sits in the White House. It'll be who's in control of the Senate and who's in control of the House of Representatives," Quigley said.
Quigley praised Biden for his accomplishments during the last three-plus years, but expressed reservations about the November election.
"I thought Joe Biden was the best person to beat Donald Trump before. I think we have to continue to assess the situation now," Quigley said.
Quigley said it may take a downturn in the polls to convince Biden to end his campaign.
"There's where we'd like voters to be, and there's where they are. We have to live with where the voters are. So, a lot of that decision-making process is going to be dependent on the snapshot we get right now in the coming days," he said.
Congressman Sean Casten, D-Downers Grove, said it was a bad debate for both Biden and former President Donald Trump.
"This debate is ultimately a referendum on the future of democracy. It's not a referendum on whether or not the president is going to be an old man. That's true, regardless of which way you decide," Casten said.
On Tuesday, the White House press secretary continued to defend the president.
"I would not see this as an episode; I would see this as what it was, and what we believe it to be. It was a bad night, and, he did, on top of that, he had a cold," Karine Jean-Pierre said.
But Casten believes the president himself should step up more to alleviate public concerns following the debate.
"I think the right thing for the White House to do is to do more public press availabilities, and show that this was a one-off event. But, there are much more important things in this election than whether or not someone is good at debating," Casten said. "If we have a lot more events like that debate that continue to raise those concerns, that's a different conversation."
On Monday, the Democratic Governors Association had a phone call, in which they discussed concerns about the debate. Pritzker did take part in that call. He is also expected to take part in a conversation the DGA is working on holding with the White House Wednesday.
Like Quigley and others, Pritzker acknowledged the president has an electoral challenge ahead of him.
But with just over 120 days till the election, the challenge now for Biden is to change a growing perception that his best days are behind him.
"President Biden needs to communicate more. We haven't heard a lot from him since the debate. And that's why the polls look as they do. I think that when you come off a bad debate, you need to remind people why you're the right guy to elect and I know that Joe Biden will do that over the next couple of weeks, at least I expect him to or he'll make a different decision," Pritzker said.
Biden will sit down with ABC News' George Stephanopoulos for his first interview since the debate. The ABC News Exclusive will air at 5:30 p.m. Friday on "World News Tonight" with David Muir.