I feel that you are being too simplistic, particularly when this issue isn't limited to our defenders but everyone in the team. Everyone on the caf has complained about the lack of availability and passing options provided to the ball carrier and our defenders aren't different, they don't have options when they are on the ball and will be under pressure when pressed because there is no simple exit options other than hoofing it. This comes back to our piss poor midfield organization, the ones that can't create, recycle, press or cover.
I have said it since 2014, in football center midfield is everything if you are not sound in that area everyone else will suffer. If we fix it, we won't complain about attackers not playing like DMs and defenders not being wannabe play makers because it's not there primary roles. It's probably the thing that bothers me the most and why I end up defending Smalling or Martial like I do, for some reason we refuse to point to the most obvious weakness and focus on things that aren't even universal among top teams. We are shit in transition because our midfield is shit, not the players but the actual midfield, it's one of the worst unit I have seen at a big club.