The Indianapolis Colts simply cannot stay healthy defensively. The cornerback group has been a mangled mess ever since training camp, and the defensive front recently lost DeForest Buckner for at least four games. A couple of aspects about Lou Anarumo's group must improve, though.
One is pass coverage in the middle of the field. The inside linebackers have been atrocious in that area, and whether it's scheme or talent, the problem must be fixed. Great offenses will take advantage of it.
Another area is the pass rush. Only Laiatu Latu has been consistently good at putting pressure on opposing QBs.