History tutors in some Houses are warning concentrators that many of the department’s star professors will be on leave next year. A total of eighteen professors affiliated with the history department will be on leave for either all or part of next year.

“This is slightly more than usual,” said David Blackbourn, Coolidge Professor and chair of the history department, who is also one of the professors on leave next fall.

Blackbourn said the departures were the result of a hiring spurt over the past few years of junior faculty members. Customarily, junior faculty members take sabbaticals after their third year at Harvard.

In addition to the numerous junior faculty members taking leave, some instructors with prominent positions and popular courses are also temporarily departing, including College Professor William E. Gienapp, who teaches the popular course “Baseball and American Society,” Professor James T. Kloppenberg, who offers several popular intellectual history courses, Professor Joyce E. Chaplin, the head tutor for the department, and Professor Lisa M. McGirr, who leads “The United States in the 1960s.”

Arthur Hock, coordinator of undergraduate studies in history, said that the department will take on visiting professors, which may help fill some holes in course offerings.

Those in the department do not feel the absence of their colleagues will harm the quality or breadth of course offerings.

“We don’t just leave a blank. There will be a lot of visitors,” said College Professor and Phillips Professor of Early American History Laurel Thatcher Ulrich.

However, Hock acknowledged that while visiting professors may fill gaps in course offerings, their presence will not improve the shortage of faculty who can serve as thesis advisers.

“I wouldn’t recommend a visiting professor for thesis advising, especially if he is going to be here for only a semester,” Hock said.

Blackbourn said graduate students were unlikely to compensate for the loss of faculty advisers.

“It is possible to have graduate students advise a thesis, but it is regrettable that we will have to lean more on them because we try to involve faculty more in writing theses,” he said. “This will be a blip for senior theses.”

Visiting professors pose still another problem, Blackbourn said. The department has hired leading scholars, but because students may be unfamiliar with these professors, courses are more likely to be undersubscribed.

“They are not in our CUE Guide,” Blackbourn said.

He described the German and intellectual history course offerings as “denuded” and said American history thesis writers could face difficulties in finding an adviser.

“There is a disproportionate number of students interested in American history,” Blackbourn said.