Pot Roast Meat is Discolored/Dark Brown....is this ok?

I'm making pot roast and was going to use an angus beef top round roast I just bought today. In the package, it looked fine, but when I opened it, on the underside, there was a part that was frozen solid and patches of REALLY dark brown....I was just going to cut off that piece, but it when down to the middle of the meat (wasn't just at the surface). I just bought it today at a reputable place and the freshness date is tomorrow. Is this ok to cook?

ALSO, it smells fine and is not slimy