You might consider a combination. First thing I would suggest is to do some soil tests and find out what it really needs. Assuming this is a long term lease, after you get the soil test results, be clear with the owner who pays for fertilizer, lime and for how long.

Apply fertilizer and have someone custom hay maybe one or two crops this year and graze the third, assuming we get enough rain. Then you'll have a better picture for next year. As said above, forget the corn. A good stand of grass is valuable and takes years to re-establish after sprayed corn. 

Maybe consider grazing it down and interseeding some legumes at some point. If you graze it make sure to do rotational grazing to get the maximum number of cow-days out of it, reduce weed pressure and to concentrate the manure

Good luck.