Sell-by dates are arbitrary. Unless we're talking infant formulas or the odd dairy product they don't mean much.
If the meat is cryo'd it has a better chance than if it was re-packed for retail. What can occur is the beginning of spoilage. This is rather unlikely to cause any illness (pathogens cause illness, not spoilage bacteria) but it can cause off flavors and/or odor.
If you can keep the roast very cold it will likely be fine, irrespective of its packaging. If not, or if unsure, it won't do any harm to stick it in the freezer for a day.