He has passed every test so far, as has his team, though bigger ones await as the days get shorter and the stakes get higher in the Big Ten and beyond.
With the Buckeyes off this week, let’s assess what they have done and what is on the horizon:
It all starts with a dominant front on both sides of the ball.
Ohio State’s defensive line is typically good, particularly with the addition of coach Larry Johnson to the mix in 2014, but this unit was expected to excel thanks to the return of most of the major contributors and the maturation of some star recruits into sophomores.
Even with a handful of members of the rotation dealing with injuries, this unit has been as good as advertised. Junior Chase Young leads the way with 9.5 tackles for loss and 8.5 sacks while senior Jashon Cornell is excelling (five tackles for loss, 2.5 sacks) in his first time as a starter.
On the other side of the ball, a unit with four new full-time starters has impressed so far, especially the last time out when Thayer Munford, Wyatt Davis, Josh Myers, Jonah Jackson and Branden Bowen paved the way for 323 yards rushing against Michigan State.
Football Outsiders advanced stats love the Buckeyes on both sides of the ball, ranking the offensive line No. 4 in the country and the defensive line No. 5 adjusted line yards.
J.K. Dobbins and Master Teague have stepped up to the plate.
Dobbins, a two-time 1,000-yard rusher already, declared last season a failure for him personally and vowed to return to his dynamic freshman form this fall after a solid-if-unspectacular-sophomore season.
So far, he’s been even better, running with more power and authority than at any point in his career and entering this weekend leading the Big Ten with 826 rushing yards and a robust 7.1-yard average per carry.
Day identified backup running back as an area of concern in the preseason, and Teague has answered the call, running for 416 yards and averaging 6.3 yards per pop as a redshirt freshman.
The passing game has barely missed a beat.
It’s hard for a five-star prospect to live up to the hype, but quarterback Justin Fields has done that so far, ranking in the national top 10 in points accounted for and passing efficiency while also showing flashes of what he can do as a runner.
Day has stressed the need for him to hone his decision-making while gaining experience, and so far Fields has avoided the big mistake while learning when to go for the big play.
Despite the loss of three productive fifth-year seniors, the Ohio State receiving corps has performed well. Seniors K.J. Hill (27 catches for 275 yards) and Binjimen Victor (18 catches for 348 yards) lead the way in catches and yards, respectively, while sophomore Chris Olave and freshman Garrett Wilson have offered hints at what they can do down the road.
The tight ends have also been a big part of the offense, providing great flexibility for the coaching staff to use different personnel groupings and offering another option in the passing game (a combined 10 catches for 124 yards and three touchdowns).
The defensive back seven is enjoying a renaissance.
After a rough 2018, members of both units have looked strong under new management.
The linebackers, led by senior Malik Harrison (28 tackles, nine for loss, 3.5 sacks), look more confident and aggressive at the direction of new coach Al Washington, who also has junior Baron Browning (23 tackles, five for los, 2.5 sacks) playing the best football of his college career.
Pete Werner is also excelling in a hybrid role as a linebacker on some plays and a defensive back on others, giving the coaching staff flexibility to change defensive looks without changing personnel.
The kicking and punting games are strong, both bolstered by great coverage units, and Ohio State has blocked three kicks.
However, the return games still leave something to be desired, particularly considering the embarrassment of riches the team has at receiver and running back.
Bottom line: The coaching staff hit it out of the park in the first half, but many challenges await.
With more comprehensive schemes on both sides of the ball, Day and his staff have made Ohio State harder to defend and harder to attack.
Even when things have gone wrong initially or they have gotten a curveball, the Buckeye coaches have been quick to adjust and proven to have answers for everything.
That is about all one can ask of a staff, right?
Well, the bottom line is college football is still about the Jimmys and the Joes even more than the Xs and the Os. A coach’s most important task is putting players in position to succeed. From there, sometimes they will and sometimes they won’t.
Last season provided a good example of that as a historically bad defense was the result more than anything of lack of execution. The scheme could have been better, but often there were players in position to make plays and they simply did not. That is still a coaching issue, but it is different from drawing up a scheme that just won’t work.
This season, Hafley and co-defensive coordinator Greg Mattison have done more to play to the strengths of their players, but those players have also played with better fundamentals – not to mention confidence and sometimes outright joy.
The offensive line has benefited from an upgrade in raw talent, but it is also responding to being relied upon more, something that also happened late last season. More opportunities to run and more options for doing so have led to better performance and results so far in 2019.
Michigan State, by far the best team Ohio State played in the first half, lost by double digits but exposed some things the Buckeyes can fix.
The Spartans were able to pressure Fields and gum up the running game early, and their offense managed to isolate players in coverage a handful of times and hit big gains through the air. They also had some success on constraint plays, including quarterback keepers.
None of that is cause for major concern, but it is a reminder these Buckeyes are human – and that they can be even better.
In the past two seasons, complacency has been Ohio State’s biggest enemy.
Could that happen again? That’s the biggest test for Day to pass.
A Friday night game at Northwestern seems like a good opportunity to try to sleepwalk to a win, but the Wildcats have not shown enough firepower to make them seem likely to pull it off even if they are better than their current 1-4 record.
After an Oct. 26 visit from Wisconsin should be easy to get up for, Ohio State has another week off before a visit from Maryland and a trip to Rutgers. The Terrapins have an intriguing offense while the Scarlet Knights have an interim coach and players debating if they even want to suit up the rest of the season or save a year of eligibility.
Finally, a Penn State team currently in the top 10 will be Ohio State’s Senior Day opponent before a trip to Michigan to finish things out.