Story highlights Johnson suggested McCain's dissenting vote on health care might have been influenced by his recent brain cancer surgery

He quickly distanced himself from the comments

(CNN) Sen. Ron Johnson on Thursday walked back controversial remarks he made about Sen. John McCain earlier in the week when he suggested the Arizona Republican's dissenting vote on health care might have been influenced by his recent brain cancer surgery.

Speaking on CNN's "New Day," Johnson, R-Wisconsin, explained that he was "just expressing sympathy," and that McCain was "not impaired in any way, shape or form" when he cast his crucial "no" vote on health care reform late last month.

On Tuesday, Johnson had suggested in a radio interview that McCain's brain tumor and the early morning hours may have affected his vote on the Senate bill to repeal Obamacare.

"Again, I'm not going to speak for John McCain -- he has a brain tumor right now -- that vote occurred at 1:30 in the morning, some of that might have factored in," Johnson said on AM560 "Chicago's Morning Answer."

Seemingly shocked, a radio host responded "really?" to Johnson's comments and asked if he really believed McCain's brain tumor might have factored into his judgment.

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