One of those departing starters - outside linebacker Tahir Whitehead - was a fourth-round pick by the Detroit Lions in April's NFL draft.
Adrian Robinson, a rookie free-agent outside linebacker for the Pittsburgh Steelers, is another talent the Owls must replace.
Robinson had 24 career sacks as a four-year starting defensive end at Temple. The Harrisburg native set the Owls' single-season sack record (13) in 2009.
But so far, Robinson hasn't been missed.
The Owls defense has dominated training-camp practices. A lot of that has to do with the play of the defensive line, the most talented group on the team.
Temple has a preseason all-Big East selection in junior nose tackle Levi Brown. Senior John Youboty moved from defensive tackle to his natural defensive-end position. Junior defensive tackle Kamal Johnson, who had one start last season, and senior defensive end Marcus Green round out the starting lineup.
Two former starters, Shahid Paulhill (defensive tackle) and Kadeem Custis (defensive end) should see plenty of action on a second unit that includes Sean Daniels (defensive end) and Hershey Walton (nose tackle).
"All of these guys have played a lot of football," Heater said. "They were all a part of a very successful defense two years ago. They were all a part of a very successful defense last year."
Though undersize and unproven, Nate D. Smith could become an impact player at middle linebacker. Smith, the younger brother of former Eagles tight end L.J. Smith, had a game-high 12 stops in the spring game.
The 5-foot-11, 230-pound redshirt freshman has been all over the field during training camp.
"I'm confident in everybody that we have in place right now," Brown said. "Even our backups are playing well right now.
"Everybody is fighting to get better. You can't get mad at that."
Note. Junior wideout Mike Doty decided to leave the team on Sunday. The walk-on served as Temple's holder for field goals and extra points last season.
Contact Keith Pompey at 215-854-2939 or email@example.com. Follow @pompeysgridlock on Twitter. Read his blog, "Owls Inq," at www.philly.com/owlsinq