It’s not too often you will see three linebacker sets because of the way the NFL has transitioned. Defensively, the Detroit Lions spent nearly three quarters of their snaps in the nickel package alone. When they employ their base 4-3 alignment, I believe the third linebacker could very well end up being Antwione Williams.
Injuries opened the door for the former Georgia Southern product to get some very valuable snaps as the third linebacker. He responded by holding his own, even starting three games.
You need to be big, athletic, fast and have bad intentions to be a strongside linebacker.