The major problem in evaluating line play is the dearth of statistics to verify performance (that, and I cannot harp on this enough, is that most opinions on line play is people parroting the generally agreed upon narrative, which often has no basis in actual performance). Now, we move on to linebackers, where the problem is the exact opposite: too much data.
Linebackers touch upon every aspect of defensive performance, and like everyone, their performance is dependent on how the others perform as well. It’s nearly impossible to separate linebacker performance from the noise.
So the method here is to look at overall defensive performance and our old friend ATVSDPI, which essentially takes our QB statistical toy, and applies it to defensive performance: what is the average modified yard per play allowed?