Tyron is having surgery to repair the torn hamstring. This means at least one of the 4 muscles that make up the hamstring detached at one end. The surgery will attempt to re-attach the muscle. This takes a long time to heal. Can he come back this year? Sure, there is a chance in 4 months he can come back, but like players with torn pectoral muscles or torn biceps he is more than likely done for the year. At his age and given his history of injury, he might be done for his career.
IMO, the Cowboys should treat this as if Tyron just retired. If the long term plan was to move Tyler Smith to LT, then do it. Now they are down Tyron, Cooper, Gregory, La'el Collins, Michael Gallup, and Ced Wilson. We have to be honest about the roster. This is going to be a down season for Dallas.