Cornerback is one of the hardest positions to evaluate with advanced metrics alone.
The best corners are obvious because they either allow a low completion percentage, are rarely targeted, or wrack up a ton of batted balls and/or interceptions. But even that isn’t enough to decide if a cornerback is entirely good or bad.
Take Cowboys CB Trevon Diggs, for example. He made the Pro Bowl and All-Pro team after leading the NFL with 11 interceptions, but he finished with the 84th-best Pro Football Focus grade and allowed the ninth-most yards per completion.
