The AP Third-Team All-American was one of four players to leave the Terps via the transfer portal on Tuesday.
After battling injury and ailment, Owusu will leave the Terps following another loss in the Sweet 16.
Dziuba is the fourth player to transfer into Mark Turgeon's program this offseason.
Martinez adds to the Terps' guard depth, while Hamilton was squeezed out of the rotation.
Smart played in 22 games as a freshman, tallying 30 points.
Russell averaged 14.7 points, 4.5 rebounds and 4.5 assists with Rhode Island this season.
Wahab fills a desperate need for the Terps in the low post.
Campbell led the Terps with 10.5 sacks per game in 2020.
The Terps also secured wide receiver Marcus Fleming as a transfer from Nebraska.
He entered the transfer portal Aug. 21.