They built a tub around that field when they sunk it so I have no idea why they cannot put in grass.
I remember the clumping issue but did not recall lack of sunlight being the reason.
Ohio State says it was contributed to wear, drought, and sod that wouldn't root:
Fierce wear, a drought, and a batch of sod that wouldn’t root forced the replacement of the field twice during the 2006 season.
https://library.osu.edu/site/ohiostadium/renovations/nggallery/image/1990_grass_install/
OSU Goes Back to Artificial Turf
Dec. 1, 2006
Ohio State will revert back to artificial turf on its football field after problems with the natural grass forced the university to lay new sod twice this season.
The athletic department made the decision this week, and the change in surface will provide a more durable, consistent field for the Buckeyes, said Don Patko, assistant athletic director for facilities management.
The stadium, built in 1922, had its grass field replaced by artificial turf in 1971. In 1990, university officials switched the field back to natural grass.
Coach Jim Tressel advocated reverting to an artificial surface after players complained that the new sod laid this season was slippery and dislodged in chunks.
"What I am pushing for is a consistent surface," Tressel said. "And then, the bonus of artificial turf would be the chance to have a lot more use."
This season, the worn out turf was replaced a third of the way through the team's schedule, at a cost of about $100,000. Three games later, the field was resodded again, this time for $67,000, after the first round of sod developed brown patches and tattered edges.
Entire article:
https://www.cleveland19.com/story/5755772/osu-goes-back-to-artificial-turf/