Grizzlies general manager Chris Wallace announced in a team release that Selden has been signed to a multiyear contract. Terms weren't disclosed.
Selden, 22, has averaged 18.5 points, 4.8 rebounds and 2.9 assists in 35 games for the Iowa Energy, the Grizzlies' NBA Developmental League affiliate. The 6-foot-5 Selden played three games for the New Orleans Pelicans this season and averaged 5.3 points, 1.7 rebounds and 15.7 minutes.
Douglas played 24 games for the Grizzlies this season. He averaged 4.9 points, 2.5 rebounds, 2.3 assists and 16.4 minutes.