I was in Sam's Club the other day and bought an Eye Round Roast. The meat department employee told me this is the same slab of meat they cut rib eye steaks from. I was skeptical, because the meat was way too lean, and nearly zero marbling. Also the cross section of this roast looks nothing like a rib eye at all, it was just like a solid red log of meat.
Anyway I did a great job cooking it, I made my own beef marinade injection, and injected it first, and marinated it, for 2 hours, then put in my grill for about 3 hours low and slow at 250 degrees, measured at the height of the top of the roast about 4" off the surface of the grill grate.
It cooked beautifully, it was super moist and juicy, as I sliced it the juices flowed wonderfully from the roast. The problem is this roast was super tough, so tough in fact that I had a real hard time getting the knife to even slice this this roast. This was the worst piece of meat I think I ever bought, it was tough to even chew it. I measured 138 degrees at the center of the roast when I removed it from the grill, medium rare. It was not over cooked nor under cooked.
I've been doing this so long and never had any screw-ups, so I doubt it's anything I did. Is this a problem with eye rounds? I'm suspicious about this type of cut, because none of my dozen or so BBQ cookbooks have any recipes or instructions for it, which tells me most people probably avoid this cut. See photos below that I shot during the cooking: