Sliders is VERY close to the stadium. It's across the street from Oriole Park at Camden Yards and just up the street from M&T Stadium. It will take you maybe 5 minutes or so to walk to the stadium from Sliders. Check the thread pinned at the top of this forum or check in the Balt/DC Area Events forum for more info.
I've been to Pgh numerous times and I've been to FatHeads before. It's been quite a while, but I do remember they had good food there. I grew up in Erie Pa, just a 2 hr drive from Pgh and my father lived there for about 16 years when I was a kid, so I do know the area somewhat.