The 59-year-old Leach was hired in January to replace Joe Moorhead after coaching at Washington State for eight seasons.
Dolson has served as IU's deputy director and chief operating officer of athletics since 2009.
The 11th-seeded Hoosiers (20-12) will now play sixth-seeded Penn State (21-10).
He's a redshirt sophomore tight end.
Neil Callaway will be senior analyst.
The Tigers also won AP titles in 2007 and 1958.
Tagovailoa, who had surgery on his right hip in November, announced his decision Monday.
IU fans have flooded the Florida city to show their support for the Hoosier football team.
Butler will open Big East play at St. John’s on Tuesday.
No. 1 LSU and No. 2 Ohio State each placed three players on The Associated Press All-America first team released Monday.