U.S. District Court Judge Lewis Kaplan on Thursday rejected one of President Donald Trump's expert witnesses in a trial to determine damages after the former president was found liable for defamation of writer E. Jean Carroll.

Noting that the trial was set only to determine damages, Kaplan ruled that five of the six requests made by Carroll's attorneys were moot. Earlier this year, Trump was found liable for defaming Carroll while denying he raped her.

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But the judge granted a request to preclude the testimony of Robert J. Fisher, a witness for the defense who intended to rebut expert witness Professor Ashlee Humphreys.

Kaplan's order pointed to another court ruling that found Fisher unreliable.

"Mr. Fisher does not explain how his experience informs his criticisms of [Professor] Humphreys's proposal for reputation repair," the prior ruling found. "Indeed, his entire analysis of [Professor] Humphreys's proposal for reputation repair contains no citation other than to [Professor] Humphreys's report."

In rejecting Fisher, Kaplan indicated he agreed with the ruling.

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"Mr. Fisher's report in this case suffers from the same inadequacies," Kaplan wrote. "The first six and a half pages of his twelve-page report contain 'a mixture of legal opinions ... as well as arguments about the evidence[] ... and sundry other things', none of which is a proper subject of expert testimony."