Still $35 million in the red, the Faculty of Arts and Sciences has maintained a restriction on the hiring of visiting professors, instead favoring the use of less expensive post-doctoral students to fill teaching positions.

But department administrators say the partial hiring freeze has affected their curricula, leading to the downsizing of certain specialized areas of instruction that are typically taught by tenure-track faculty.

“We aren’t offering fields because we don’t have visiting lecturers,” said History of Art and Architecture Department Administrator Deanna Dalrymple. “It’s a visiting lecturer that typically teaches a certain field or topic when we think there is a perhaps a deficiency in our curriculum. We don’t currently have that capability.”

For the past two years, FAS has cut costs by hiring the comparatively cheaper teaching fellows through the newly-established College Fellows Program, which helps provide one-year teaching opportunities for Harvard graduate students entering a difficult job market.

The Government Department currently has three college fellows and plans to keep the number the same in the next academic year, according to Government Department Chair Timothy J. Colton.

The number of college fellow hires has fallen short of the numbers needed to cover the vacancies of professors on sabbatical, department administrators said.

There has been a tangible decrease in the number of lecturers in the Psychology Department over the past four years, according to Department Chair Susan E. Carey ’64.

“We are definitely influenced by the budget deficit,” she said.

And with more professors opting to take the FAS retirement package offered last fall to faculty over 65, administrators questioned whether they might have enough resources to plug the hole created by retiring tenured professors.

For example, although there is a greater number of lecturers in the Psychology Department this year, the increase can be attributed to a rise in the number of professors leaving their posts, said Undergraduate Advising Administrator Laura L. Chivers.

Not every department has completely frozen the hiring of visiting professors. The Economics Department, for instance, saw the number of visiting professors increase last year, which contributed to the resurrection of junior seminars in that department.

“I know [hiring visiting professors] has been harder, but obviously that doesn’t affect me because I am here,” said George-Marios Angeletos, a visiting professor of economics from MIT.

­—Staff writer Gautam S. Kumar can be reached at gkumar@college.harvard.edu.

—Staff writer Sirui Li can be reached at sli@college.harvard.edu.

This article has been revised to reflect the following correction.

CORRECTION: FEB. 25, 2011

The Feb. 24 article "Limit on Visiting Faculty Continues" incorrectly stated that the Government Department will be hiring three additional College fellows in the next academic year. In fact, the department will maintain the number of fellows at three next year.