Yeah, an off-campus stadium is an option. It's an option that's been dismissed, but it could be said that it's an option.
I don't know what Mahoney (or, don't forget, the local reporter) meant by "informal agreement." Chancy Nancy liked the idea of some midtown stadium construction, creating synergy among her Connective Corridor, Upstate's new campus, Hawley-Green, and downtown. (I hate the idea but saw where she's coming from.)
Kent and other decision-makers do not like the idea. It was dead in the water once he weighed in against it. I doubt SU and the county had an informal agreement other than "Nancy likes this idea and isn't opposed to our pitching the governor on contributing funding to its construction."