PITTSBURGH (AP) A year ago, the defensive game plan for Pittsburgh was pretty simple: let all-everything defensive lineman Aaron Donald to go work and try not to get in his way.
Following a season during which he won every major award for players at his position, Donald took his 28.5 tackles for loss and 11 sacks to the NFL, turning a position of strength in 2013 into a question mark with three weeks left before the 2014 season opener against Delaware.
''We've talked before about replacing Aaron,'' coach Paul Chryst said. ''You're not going to replace one guy's production with one guy, but collectively.''
The Panthers also lost Donald's running mate on the interior line, Tyrone Ezell, who compiled 34 tackles, three for loss and a pair of sacks last year.
Even though the player known as ''A.D.'' within the program departed, his impact still lingers. Defensive line coach Inoke Breckterfield says he invokes Donald's notorious work ethic relentlessly.
''He is a great guy to mold your game to or to just mold your mindset,'' Breckterfield said of Donald. ''We come back to him all the time and he was a great example for the young guys.''
Now it's time for Donald's understudies to take center stage. Khaynin Mosley-Smith and Darryl Render appear to have the inside track to run out of the tunnel with the starters on Aug. 30 when the Panthers face the Blue Hens.
''They have been running with the (first team),'' Breckterfield said. ''We are trying to roll in Tyrique (Jarrett) and Jeremiah (Taleni). We are trying to give everyone a shot and we just want (everyone) to play hard and fast.''
Render, a junior, is one of the more experienced linemen after playing in all 13 games last season. He recorded 25 tackles in 2013, 2.5 for loss, and says he is always trying to take what he learned from Donald onto the field.
''Every day I come out and try to remember little keys (Donald) gave me with pre-snapping and post-snapping,'' Render said. ''The (spot) I'm supposed to get and what I'm supposed to do when I get (there).''
Breckterfield noted Render's weight loss in the offseason -down to between 280-285 pounds- as proof of Render's intent on emulating the undersized Donald.
''I think his strength is a little better and he still has to clean up some stuff,'' Breckterfield said. ''But I think he is playing at a high level. He is giving everything on every play and has got some stuff in the pass rush.''
Mosley-Smith, on the other hand, did not take a single snap last season due to a yearlong suspension for violating team rules which he believes made him ''mentally stronger.''
''My family was behind me and pushing me,'' Mosley-Smith said. ''Coach Chryst was pushing me, and just making me a better person through all of that last year.''
Mosley-Smith played in 13 games as a sophomore in 2012 and recorded eight tackles in his first full season. In 2013 his only experience playing the game was on the practice field, watching and sometimes playing next to Donald.
''He taught me a lot,'' Mosley-Smith said. ''I have picked up things like ways I can beat my opponent.''
But with Donald gone, it's up to Mosley-Smith, Render and others to be the ones beating their opponents, as Donald did many times last year. The impression he left behind is a good place to start for those needing to assume his production