Other than Osa Odighizuwa, the Dallas Cowboys don't really have any starting caliber players at the defensive tackle position, at least not proven anyways. Expecting Mazi Smith to take a significant second-year jump to become a full-time starter seems like a pretty optimistic approach to take, but that seems to be the direction the Cowboys are going.
Unfortunately, Dallas has done little to nothing to upgrade the DT position so far this offseason other than drafting Justin Rogers in the seventh round. Because of that, the lack of talent/depth is by far their biggest roster concern right now.