I have harped on this before with Day but this year showed the issue again.

From 2005 to 2016, OSU ranked in the top 30 in rushing yards per game every year 

05 - 24th, 06 - 26th, 07 - 28th, 08 - 24th, 09 - 18th, 10 - 14th, 11 - 27th, 12 - 10th, 13 - 5th, 14 - 8th, 15 - 11th, 16 - 11th

Day gets here in 2017 as OC. Since his arrival here are the teams rush offense rankings

17 - 17th - JT still QB

18 - 63rd

19 - 5th - Fields

20 - 8th - Fields again

21 - 47th

22 - 32nd

23 - 87th

24 - 60th

5 of 8 seasons outside the top 30, where in the previous 23 years we were outside the top 30 only 5 times dating back to 1994...

The average ranked= from 2005 to 2016 was 17th

Since Day got here it is 40th

The reality is, that without a true dual threat QB, Day has been unable to have a good to great run game. His best was when he had Dobbins here and came close at 32nd, which is still 4 spots lower than the 12 years before him. 

His O line are weak period