We have a similar post to this already but I'm going to mention talking points (for and against) we have heard for each one, but adding the head coach this time: who do you think is ultimately responsible?

Knowles:

• Overall increases in defensive efficiency across the board since he has been here. We have been a top 5 defense "on paper" the last 2 years he has been here.
• Has historically ran an aggressive scheme that incorporates blitzing and varied coverages to confuse opposing offenses, but seems to be limited by LJ's defensive line set.
• Consistent theme with his defenses falling apart in big games and his defensive stats are getting padded against much lesser teams.

LJ: 

• Legend and Hall of Famer
• Has produced legends at Ohio State including both Bosas and Chase Young
• His 4 down sets are becoming less common in contemporary football due to changing offensive dynamics and the increasing amount of nickel packages and hybrid defenses.
• Lack of rotation on the defensive line.
• Have witnessed a severe lack of development on OSU's defensive line since those guys have graduated. Have two 5 star defensive ends who have underperformed in comparison to their ratings out of high school.
• His defensive tackles have never achieved the same level of recognition or production that his defensive ends did.
• Possible questions that the superior talent levels of both Bosas and Young would have given them amazing careers no matter what university they attended.

Day:

• Has always been seemingly willing to adapt and has shown he is not afraid to overhaul his coaching staff if needed.
• He is not afraid to take criticism (as shown recently with Saban).
• The buck also stops with Day and he has made some questionable decisions for his defensive staff:
  • While Hafley was seemingly a great hire, his departure left a huge gap at DC that was filled by Kerry Coombs (a first time ever college DC). This led to one of the worst modern day OSU defenses and some of the worst pass defenses in college football. In 2021, our pass defense ranked 122 out of 130 FBS teams.
  • In 2022, Coombs was kept on staff and Barnes was promoted to co-DC with Coombs. While there was a slight improvement, our pass defense still ranked 86 out of 130 FBS teams.
  • In 2023, Day shows a willingness to make a major change and bring in Knowles, which has seemed to pay dividends. However, he ultimately made a choice to hire a DC who has clear conflicts in defensive philosophy with his current defensive line coach (with no plan to get rid of LJ or force him to adapt), and has yet to do anything to correct that error after 2 years.