After months of casting President Joe Biden as a shell of a man incapable of putting two sentences together, Donald Trump has changed his tune days before their first debate.

"I assume he's going to be somebody that will be a worthy debater," the former president and presumptive Republican nominee said in an appearance on "The All-In" podcast last week.

"I don't want to underestimate him," he added.

The changed rhetoric marks a dramatic shift from how Trump typically describes the man he will face in a rematch this November. At his rallies and in speeches, Trump typically casts the Democratic incumbent as a "low-IQ individual" who is "the worst, most incompetent, and most corrupt president" in the nation's history, and often imitates Biden appearing lost on stage.

The effort to adjust expectations ahead of Thursday's matchup in Atlanta comes amid concerns from some in his party that Trump has set the bar so low for Biden that he is sure to exceed it. And it underscores the stakes for both men in a race that has appeared largely static for months.

Millions are expected to tune in Thursday, offering a rare opportunity for both sides to try to gain momentum in a contest that will likely be decided by a small fraction of voters in a handful of battleground states.

Trump — who has never admitted he lost fairly to Biden in 2020 and continues to spread false and unproven theories about election fraud — may also be setting up a series of excuses in case he is outperformed by Biden.

"Maybe I'm better off losing the debate," Trump quipped in an interview with Real America's Voice earlier this month. "I'll make sure he stays. I'll lose the debate on purpose, maybe I'll do something like that."

It's not just Trump who has been talking up Biden. On Sunday, North Dakota Gov. Doug Burgum, one of Trump's chief surrogates and a top vice presidential contender, pointed to the president's experience on the debate stage.

"This guy has got the ability," he said on CNN's "State of the Union." "We have seen him in the State of the Union this year, that, when he needs to, he can step up."

At the same time, Trump and his campaign have ramped up their attacks on the debate's moderators, insisting the former president won't be given a fair shake by CNN, which will be hosting the debate. Both campaigns accepted CNN's invitation after deciding to sidestep the nonpartisan Commission on Presidential Debates, which had hosted debates for decades.

"I'll be debating three people instead of one half of a person," Trump said at a rally in Racine, Wisconsin, last week.

On Monday, one of the network's hosts, Kasie Hunt, cut off Trump spokesperson Karoline Leavitt and ended their segment after Leavitt attacked Jake Tapper, the anchor who will moderate along with Dana Bash, accusing him of being biased against Trump.

The episode "shows that exactly what we're saying is true, that CNN is not a friendly Trump network, and it won't be friendly to him on Thursday night," Leavitt said after the incident on FOX Radio's "FOX Across America."

CNN, in a statement, called Tapper and Bash "well-respected veteran journalists" with "extensive experience moderating major political debates."

"There are no two people better equipped to co-moderate a substantial and fact-based discussion and we look forward to the debate on June 27 in Atlanta," the network said in a statement.

During "The All-In" podcast interview, Trump repeatedly pointed to Biden's vice presidential debate against Paul Ryan in 2012, then-GOP nominee Mitt Romney's running mate.

"Well, all I can say is this: I watched him with Paul Ryan, and he destroyed Paul Ryan," said Trump. "So I'm not underestimating him. I'm not underestimating him. It is what it is. We'll see what happens."

Complimenting Biden at Ryan's expense also allows Trump to insult the former House speaker, who was an often uneasy ally when Trump was in the White House and has since spoken out repeatedly against the former president.

Trump has not completely abandoned his insults of Biden.

At a Saturday gathering of evangelical Christians in Washington, he again went after Biden in deeply personal terms, questioning his intellect. He's even suggested that Biden would be drugged at the debate, an outlandish attack he also made without evidence during this year's State of the Union address.

"I say he'll come out all jacked up, right? All jacked up," Trump told a rally crowd Saturday in Philadelphia.

Trump campaign spokesman Steven Cheung, meanwhile, accused the media of helping to lower Biden's expectations "so low he gets a participation trophy simply for standing upright for 90 minutes" and questioned if "Biden can speak for himself without the overt participation and interference of two CNN moderators."

Biden's campaign responded by accusing Trump of trying to "distract us from the reality of Thursday night — before a general election audience for the first time, Trump will have to answer for ripping away Americans' freedoms, promising his billionaire donors tax cuts at the expense of the middle class, and threatening our very democracy with promises to rule as a dictator if he wins and violence if he loses," said spokesperson Ammar Moussa.