But their spirit lives on at USC's Heritage Hall.
"They look good up there with the other great linebackers that played here," junior Malcolm Smith said. "But we're ready to establish our own identity."
As USC prepares for its Sept. 5 opener against San Jose State at the Coliseum, the linebacker corps is in the spotlight -- but not because of its star power.
The Trojans' defense the last few seasons was anchored by a seemingly unending supply of linebackers, a situation that allowed Cushing and Matthews to also take turns as defensive linemen.
Cushing and Matthews parlayed their diverse talents into first-round recognition in last April's NFL draft, Cushing taken by the Houston Texans and Matthews by the Green Bay Packers. Maualuga was chosen in the second round by the Cincinnati Bengals, Maiava in the fourth by the Cleveland Browns.
Now comes a unit that is thinner physically and less experienced.
Smith, sophomore middle linebacker Chris Galippo and junior Michael Morgan are no longer understudies behind the leading tacklers for a USC defense that gave up only nine points a game in 2008.
"These guys have been right in those guys' hip pockets all this time and they know what our expectations were and how they played and handled themselves," Coach Pete Carroll said. "They are not as big or as heavy, but they are faster."
Linebackers coach Ken Norton has challenged his position group to show that there will be no drop in production despite the loss of such decorated predecessors.
"I'm still young in my coaching career and I was fortunate to have such great players," said Norton, who played in the NFL for 13 years and is in his sixth season with the Trojans. "But they weren't great when they got here.
"These guys have been waiting for their chance, and they think they can be just as good or better."
Galippo, a former Anaheim Servite High star, played three games as a freshman in 2007 before back surgery forced him to redshirt. Last season, he sat out the first three games while recovering from another back surgery but played in the last 10.
"This is the year," Galippo said, chuckling anxiously. "Nothing is going to happen to me, and if it does I'm not going to have it taken care of until after the season."
The 6-foot-2 Galippo reported to training camp at 238 pounds -- more than 20 pounds lighter than Maualuga's listed weight in 2008. But coaches say that what Galippo surrenders in brawn and speed, he makes up for with football acumen.
"He understands how to command the huddle and when you look him in the eye, you can see that he understands what you want him to do," defensive coordinator Rocky Seto said.
Smith flanks Galippo on the weak side after backing up Maiava and 2008 first-round draft pick Keith Rivers the last two seasons.
The 6-1, 225-pound Smith, brother of New York Giants and former Trojans receiver Steve Smith, had an outstanding spring but is still working his way back from off-season esophagus surgery and illness that dropped his weight.
Morgan, 6-4, 220, replaces Cushing on the strong side. The Texas native started against Oregon when Cushing moved to the middle because of a Maualuga knee injury, and Morgan responded with eight tackles.
"I knew this opportunity was going to come -- I just had to be patient," Morgan said. "Now that it's here, I'm ready and we're all ready to take advantage."
For the first time in several years, though, the linebacker corps is short on reserve strength.
"Depth is an issue," Carroll acknowledged.
The Trojans were counting on incoming freshman Frankie Telfort to contribute immediately, but the Miami native's Trojans playing career ended before it could begin when he was diagnosed with a heart condition. Telfort will serve as a student coach.
Uncertainty about senior Luthur Brown's status also hangs over the program. If Brown is declared academically eligible -- he is not practicing -- he would give the Trojans a player who could play all three spots, much like Thomas Williams did a few years ago.
In the meantime, the Trojans are hoping that freshmen Jarvis Jones, Kevin Greene and Marquis Simmons can contribute to a unit that also includes sophomore middle linebacker Uona Kaveinga, sophomore Jordan Campbell, fifth-year senior Nick Garratt and sophomore Shane Horton, who recently moved to linebacker from safety.
"There's some uncertainty, but this is what makes it fun," Carroll said. "We train our guys to be ready when the opportunity is there, so this is going to be a good test."