The Terps exceeded expectations in a 21-12 season that ended in the second round of the NCAA Tournament.
Willard said the forward lost about 25 pounds in order to play expanded minutes at a potentially higher tempo.
The Terps bring back three leaders in Eric Ayala, Donta Scott and Hakim Hart, all set to have banner seasons.
Coach Mark Turgeon had an active offseason in the transfer portal and the results brought players ready to make an impact.
The Terps added nine new players to their squad, but the team said they are close on and off the court already.
Wiggins' selection marks the fourth straight year the Terps have had a player chosen in the NBA Draft.
Wiggins averaged 14.5 points, 5.8 rebounds and 2.5 assists per game last season and saw his NBA stock rise.
Ayala led all Terps in scoring with 15.1 points last season.
Morsell departs from the Terps after an historic season where he became the first Maryland player to win conference Defensive Player of the Year.
Martinez adds to the Terps' guard depth, while Hamilton was squeezed out of the rotation.