The kind of questions that have no definitive answers...
Let's just hope that they are tired (a bit old), but probably not as bad as it looks.
Some numbers can be telling. It's just not red zone defense, which is an arbitrary stat (why not define red zone at 25 yds? or 27?). Total yards are not very indicative. 3rd down % is only a parameter.
It's their propensity to give up sustained drives and points, which is about average. So far, INTs save them. Otherwise, it would have been worse.
Great offense, so-so defense, you can't have everything in life, I guess.