In brief, the Buck ILB is an off-ball linebacker who is 50 lbs. shy of being a super-mobile defensive lineman - and who plays that way. Buck ILB’s are the guys with miniature footballs running through their veins instead of corpuscles, and DNA that spirals tighter than a bulleted slant to a receiver over the middle.
In terms of duties, about 70% of the Buck ILB’s attention needs to focus on heading downhill in run support and/or on an inside blitz. This is the sap [ahem!] tough guy who mans up when Rosie Nix comes barrelling forward hellbent on justifying his existence, and some poor soul has to stop him cold at the line of scrimmage. In the absence of a careening fullback your Buck ILB will routinely take on pulling guards that outweigh him by at least 30%, crash into gaps the offensive line is trying to clear, make the tackle on inside runs, and blitz up the middle on pass plays. The other 30% of his job lies in coverage duty on backs and TE’s. Buck ILB’s tend to play in the 245-255 range because they need that mass to survive the constant impacts, but it also makes them vulnerable when asked to play in coverage. They aren’t completely lost like a defensive lineman would be, but they’re likely to have a real tough time and that makes them favorite targets for a canny QB who thrives on finding the right matchup
