Northwestern is promoting Mike Polisky to athletic director, ending a lengthy search for Jim Phillips' successor, sources told ESPN.

Polisky, who has served as Northwestern's deputy athletic director for external affairs since June 2010, will be announced as AD on Monday. Phillips took the ACC commissioner job in December and completed his term at Northwestern in February.

Northwestern spoke with several sitting athletic directors about replacing Phillips but narrowed its search recently to Polisky, Duke senior deputy athletic director Nina King and several others in recent weeks, according to sources. Polisky had been seen as the favorite to succeed Phillips, but the hiring was delayed as Northwestern investigated a federal lawsuit filed by a former cheerleader that named Polisky, three others and the university.

The complaint filed in January by former cheerleader Hayden Richardson states that Polisky and the others condoned a "hostile environment" where she and other cheerleaders were subject to "groping, harassment, and sexual touching" by alumni and fans at events. The complaint states that Polisky accused Richardson of fabricating her claims, and didn't allow her to meet with Phillips.

Sources said Northwestern completed its review of the case and on Friday filed a motion to dismiss the lawsuit.

Polisky is credited with leading Northwestern's first-ever comprehensive marketing campaign for athletics, which includes calling the program "Chicago's Big Ten team." He has led a partnership with the Chicago Cubs that led to Northwestern's football team playing Illinois at Wrigley Field in 2010. Northwestern will host Purdue at Wrigley Field this fall. Northwestern's football season ticket base has more than doubled during Polisky's tenure.

The Chicago Tribune first reported Polisky's hiring.