Several colleagues are accusing Thomas Petee, interim chairman of the sociology department at Auburn University, of handing out high grades to more than a dozen football players in courses that required no attendance and little work, according to an investigation by The New York Times.

The alleged academic fraud helped the Tigers’ powerful football team post the highest NCAA Academic Progress Rate of any top public university among college football’s six major conferences. Over all, among Division I-A football programs, Auburn trailed only Stanford University, Navy, and Boston College, and finished just ahead of Duke University.

In order to supervise so many students, Mr. Petee, who denied that he fixed grades, was carrying the workload of more than three and a half professors, an academic schedule that his colleagues said no one could legitimately handle. His directed-reading classes—an independent-study course that nonathletes took as well—helped athletes in several sports improve their grade-point averages and preserve their athletic eligibility, the newspaper reported.

Professor Petee said nothing was unethical about the number of courses he taught, but he has recently reduced his teaching load.

The Auburn provost’s office has began an investigation into the allegations. Meanwhile, Mr. Petee remains the head of the sociology department.