Pitt itself would be well served, not just for football, to spread awareness of its presence to downtown beyond Oakland. That's where it began, for one. Two, I think it's one reason (not the only one by any means, but one) that the rest of the city doesn't embrace the university as PITTSBURGH'S university. They see Pitt as synonymous with Oakland, and thanks mostly to the slumlords that let south Oakland fester, see Oakland as a sh*thole, thus see Pitt as a sh*thole school (Pitt's media and city gov enemies gladly perpetuate this thinking).
However, locals seem to pat themselves on the back more for their "golden triangle" downtown (which I find far more barren and dirty than Oakland, especially evenings sms weekends but whatever... perceptions matter). Put a crappy restaurant downtown, locals automatically think more highly of it than they would if on Craig St.
I know there have been Pitt offices and satellite classes conducted downtown in the past (i took a couple). Nothing I know of permanence though. But thinking bigger ... is there any feasible synergy or potential for Pitt to annex Point Park University, which is near Pitt's birth place anyway, and conquer downtown?
Either way, relating this to football, there is a vantage point on the trail on the South side near the Tarpfire (aka Liberty) Bridge where you can see the south tip of Heinz Field on the left and the tip of the Cathedral of Learning on the right. The city CAN be thought of as Pitt's campus. A photo taken from there at a bit of elevation (a drone?) could better accentuate this proximity.
Is the annex question serious? Because the answer is no.