ORONO, Maine (AP) — University of Maine Athletic Director Steve Abbott is stepping down to return to his former job as chief of staff for U.S. Sen. Susan Collins.

The university announced Tuesday that Abbott will be leaving this fall after three years on the job and returning to Collins' office in Washington.

The 51-year-old Abbott was Collins' chief of staff for 12 years before resigning to run in the 2010 Republican primary for governor. After losing the primary, he was hired as athletic director.

University President Paul Ferguson says a national search will be conducted to replace Abbott.

Collins said her current chief of staff, Mary Dietrich, plans to retire from the Senate at the end of the current fiscal year.