Mahinmi is the type of defensive-minded center the Wizards had been pursuing to complement the dynamic backcourt of John Wall and Bradley Beal, a restricted free agent who re-signed with Washington for five years and $128 million.
Mahinmi averaged 9.3 points, 7.1 rebounds and 1.1 blocks per game this past season for the Indiana Pacers.
Mahinmi has played for San Antonio, Dallas and Indiana in his nine NBA seasons. He spent the past four years with the Pacers, serving as a rotation presence on back-to-back Eastern Conference finalists in 2013-14.
Mahinmi, 29, was the No. 28 pick of the Spurs in the 2005 NBA draft.