Both the Ohio State football team and Texas are replacing a ton of players on the trenches. The Buckeyes are replacing their entire defensive line, as well as four starters from the offensive line. Texas is replacing the exact same thing, except Ohio State has four guys who played in the CFP on the offensive line.
Texas has a lot of unproven talent on the offensive line. They were dealt a massive blow when they lost Andrew Cojee for the season with a knee injury. That leaves them even shorter on depth than they were expecting.