Originally Published: 25 AUG 22 09:27 ET

Updated: 25 AUG 22 10:53 ET

By Dan Merica and Eva McKend, CNN

(CNN) -- Mehmet Oz was quick to wish John Fetterman well and offer prayers as the Democrat recovered from a stroke earlier this year.

But now that the two are officially facing each other in one of the highest profile Senate races of 2022, the Republican Senate nominee and his campaign aides are making clear that they view their Democratic opponent's stroke -- and lingering health issues that have impacted his speech -- as fair game in the general election.

Oz's campaign, through a series of statements and comments to reporters, has already shown a stepped-up aggression on the state of the Democratic lieutenant governor's health months removed from his near deadly stroke. They have questioned Fetterman's diet, suggested he can't stand for more than 10 minutes and accused his campaign of lying about the health challenges Fetterman faces.

Fetterman and his team have responded by questioning the strategy, labeling it "grotesque" and suggesting it is even worse than politics as usual.

Oz's focus comes as the Republican candidate looks to shake off what has been a trying summer, where Fetterman -- even as he was off the campaign trail and recovering from the stroke and implementation of a pacemaker with a defibrillator -- consistently outraised Oz and opened a double-digit lead over him in some polls. The critiques stem from the fact Fetterman has yet to commit to debates against Oz.

"One candidate had a stroke 3 months ago, and the other is a professional television personality, so our eyes are wide open about whose strengths this plays to," Joe Calvello, a spokesperson for Fetterman, said in response to questions about the debates. "Still, John is up for debating Oz -- we're not going to do this on Oz's terms and timeline,"

Fetterman has said that his stroke almost killed him and that he did not do enough to look after his own health. When he fully reemerged earlier this month with an event in Erie, he said, "Three months ago, my life could have ended but I'm so grateful to be here tonight as well."

He followed up his return with a union-focused rally in Pittsburgh on Tuesday, and he will headline a rally on Sunday in Mercer County.

Fetterman's speech was halting at the events in Erie and Pittsburgh, with the candidate sometimes taking long pauses and dropping words. Democrats who attended a Fetterman fundraiser over the summer reported a similar experience with the lieutenant governor -- his speech was focused but, at times, halting.

It's something that Republicans have used to question whether Fetterman is even fit to campaign for Senate.

On Tuesday, Oz's campaign highlighted this stepped-up focus with a statement that looked to draw attention away from the now much-maligned video of Oz attacking rising prices under President Joe Biden by putting together a crudité plate -- not exactly the appetizer of the people -- at a local grocery story. Fetterman's campaign has hounded Oz for the video, including selling "Let them eat crudité" stickers and filming a fundraising video that questioned whether the wealthy Oz could actually represent the commonwealth.

In response, Oz spokeswoman Rachel Tripp lashed out: "If John Fetterman had ever eaten a vegetable in his life, then maybe he wouldn't have had a major stroke and wouldn't be in the position of having to lie about it constantly."

Fetterman's campaign has been tight-lipped on details about the candidate's recovery. A Fetterman spokesman has said the candidate is "doing really well," "walking 5-6 miles a day" and "following doctor's orders," but Fetterman has been cautious about speaking one-on-one with reporters in the wake of his stroke and discussing his own health challenges.

Oz's shift to focus on his health looks to seize on that uncertainty.

To criticize Fetterman for failing to agree to debate Oz, campaign communications director Brittany Yanick said, "If John is too sick to debate and is concerned he can not stand in front of cameras for more than 10 minutes, then he should just say so."

It's a significant shift for Oz. The candidate initially responded to Fetterman's stroke by tweeting that he was "thankful that (Fetterman) received care so quickly" and that his "whole family is praying for your speedy recovery."

Just weeks ago, when asked about Fetterman's first event, Oz said he was "over the moon" that the lieutenant governor was back to campaigning, saying, "I'd love to have him out there talking about what he wants to do to make Pennsylvania a better place."

Fetterman and his campaign have responded to Oz's attacks with calls for empathy and criticism of the strategy.

"I had a stroke. I survived it. I'm truly so grateful to still be here today," Fetterman said in response to the Oz campaign's "eaten a vegetable" statement. "I know politics can be nasty, but even then, I could never imagine ridiculing someone for their health challenges."

Fetterman's wife, Gisele, called the vegetable statement "grotesque" and Val Arkoosh, a doctor and one of the Democrats who ran against Fetterman in the Senate primary, told reporters that, "No real doctor, or any decent human being, would ever mock a stroke victim."

But Barney Keller, an Oz campaign spokesman, told CNN on Wednesday that they fully stand by their questions about Fetterman's health, including the suggestion that he eat more vegetables, and argued that the focus is primarily aimed at getting Fetterman to debate.

"I don't see how it is ridicule to encourage someone to have a healthier lifestyle," Keller said. "Nobody is attacking his health. We all hope he gets better. What we are criticizing is him lying about his health. That is an important distinction."

Keller says that the Oz campaign will continue to focus on Fetterman's health "so long as he continues to lie about it."

"Since the primary, the guy has had two Zoom interviews and two public appearance and all we are saying is stop pretending like everything is OK and just say you can't debate because you aren't not able to," Keller concluded.

Calvello responded to the accusation of lying by saying Fetterman has been "clear about his health. As he told the Pittsburgh Post-Gazette a few weeks back, he's in speech therapy, and as he told KDKA, he still has some trouble with some auditory processing."

"We're trying to have an honest conversation about health, one that thousands of Pennsylvanians have probably had with their own families," Calvello said. "But let's be clear: Last night, Oz's team made an extremely insensitive and frankly unhinged remark about John's health."

Keller's commentary reflects the way Republicans have started to argue privately and publicly that Fetterman's health is on the table as a campaign issue.

"You have to put Fetterman on defense and this is the way to do it," said a top Republican strategist working on Senate races.

The operative admitted that Oz and Republicans "have to be careful about how you talk about it," but "raising questions about his health is completely fair and on the table."

Democrats who have attended Fetterman's events have been far more forgiving.

"When someone is recovering from that serious of a situation," said Pittsburgh steelworker Jojo Burgess, "I think that he's back fairly quickly, to be honest with you."