More than 1,200 academics have signed a letter protesting to the Home Office about the "distressing" case of a research fellow told to leave the UK.
Asiya Islam, a sociologist based at Newnham College, University of Cambridge, has lived in the UK for 10 years.
Her application for indefinite leave to remain was denied because of the amount of time she has spent overseas.
But the open letter said the ruling was "unfair" because this was for research.
The letter said that the academics are "calling upon the Home Office to reconsider the decision".
It said: "Her case is distressing, but it also sends a foreboding signal that UK universities will continue to lose the talented PhD researchers that they have invested years in training."
Dr Islam, 31, originally from Aligarh in India, studied for a Masters at the London School of Economics.
She then gained a prestigious Gates scholarship at Cambridge, and after completing her PhD was awarded a three-year junior research fellowship at the university this year.
Dr Islam said: "I provided several letters to present the case that fieldwork is a crucial aspect of my work and should not count towards my days out of the country."
But she explained the letter from the Home Office said she had "failed to provide any exceptional reasons" why she was overseas.
She said: "I think in the last 10 years the immigration system has evolved into chaos."
"It's something I'm definitely going to challenge," she added.
The Home Office said each immigration application was considered on a case-by-case basis.
It said indefinite leave to remain was normally refused under a Tier 4 visa if an individual was out of the country for more than 540 days over the course of a decade.