The Grizzlies announced the moves Tuesday.
The 7-foot Hollins has started 67 of his 486 career games over 10 seasons, and Memphis now becomes his ninth team after being in training camp with the Grizzlies earlier this year. Hollins has averaged 3.7 points and 2.2 rebounds in his career.
During training camp, Hollins averaged 5.4 points and shot 83.3 percent in seven preseason games. He started three of five games for Washington before being waived Dec. 23.
Smith averaged 2 points and 0.7 assists in 27 games with Memphis and New Orleans. Memphis acquired him in a trade with the Pelicans on Jan. 12.