Ayala led all Terps in scoring with 15.1 points last season.
After transferring to Maryland in April, Russell rejoins former high school teammate Donta Scott.
Martinez adds to the Terps' guard depth, while Hamilton was squeezed out of the rotation.
The junior led the Terps in scoring last season, averaging 15.1 points per game.
Russell averaged 14.7 points, 4.5 rebounds and 4.5 assists with Rhode Island this season.
The Crimson Tide hit 16 threes to dash the Terps' Sweet 16 hopes.
“Our talent level’s not where it’s been. But our toughness is at an all-time high.”
The Terps held the Huskies to 32.3 percent shooting.
The Terps faced 10 tournament-bound teams in the regular season.
Wolverines coach Juwan Howard was ejected from Friday’s game, while Terps coach Mark Turgeon was given a technical foul for their altercation.