The release of Aldon Smith leaves a big void in the middle of the defense for the 49ers.

Defensive coordinator Eric Mangini flat-out stated: "He's not a guy you can just replace."

So who could perhaps try to fill that void?

Corey Lemonier, the team's third-round pick in the 2013 NFL Draft, appears to have first shot at winning the job outright.

Per ESPN Insider, Lemonier "has a prototypical 3-4 OLB build. He plays with a great motor and is relentless as a pass rusher, and flashes an explosive first step and ability to bend and shave the edge."

Coming out of Auburn, Lemonier recorded 98 tackles and 17 sacks. There was a drop in production from his sophomore to junior season, however (9.5 sacks to 5.5 and 5 forced fumbles to 1). He was billed as a fit in the Niners' defensive schemes when drafted, but Lemonier has yet to show much promise through two seasons.

Could 2015 be the year he finally breaks out?

(h/t ESPN)