The university says in a statement Tuesday that professor Lars Maischak has taken a voluntary leave of absence for the remainder of the spring semester.
Last week, Maischak apologized for tweeting: 'To save American democracy, Trump must hang. The sooner and the higher, the better.'
The university declined to say if Maischak would be back to teach in the fall, saying it was continuing to review the case.
Maischak said last week he has temporarily left Fresno while the university is on spring break, after receiving death threats and hundreds of hate emails.
'I regret making these tweets,' Maischak said. 'I wrote them to an audience of 28 followers on Twitter under the assumption they would be read by people I know.'
Maischak said he sent the tweet in February to voice personal despair over comments by Trump and actions by the current US government and was not trying to incite violence.
The tweet said: 'To save American democracy, Trump must hang. The sooner and the higher, the better. #TheResistance #DeathToFascism.'
University President Joseph Castro said he appreciated Maischak's apology, calling it 'a first good step' in calming critics.
The university was committed to free speech and was taking the matter seriously, Castro said.