Mariota hasn't seen much drop off in his passing stats since the injury, completing 39 of 60 passes for 538 yards and five touchdowns in his last two games, and he still hasn't thrown an interception this season.
But Mariota's rushing attempts and yardage have gone down precipitously since the injury, while his sacks have gone up. Since putting the brace on in the second half of a win against UCLA, Mariota has carried the ball 18 times and lost 21 yards, including six sacks for a loss of 44 yards.
Mariota had been averaging just over 10 yards per carry in his first seven games this season, rushing for 493 yards and nine touchdowns, while Oregon was allowing just over one sack per game.
That has carried over to the Ducks' run game as a whole, leading offensive line coach Steve Greatwood to quip, "I must be screwing up for all this kind of attention. Are we playing that bad?"
In their last two games, the Ducks rushed for 62 yards in their loss at Stanford, ticking up slightly to 145 yards in a win at Utah.
Greatwood admitted the threat of Mariota as a runner limits how opposing defenses can play, but the injury is not the only reason for diminished production -- credit should also go to the talented defensive fronts of the Cardinal and Utes -- but the Oregon offensive line shoulders much of the blame.
"It keeps defenses a little more honest when you have that threat, but we can't use that as an excuse," Greatwood told the Oregonian. "There was a couple of plays, some short yardage plays that we got stuffed on that it wouldn't matter if Marcus had wings and could fly.
"We've got to execute what we're supposed do and pick up the right guys. That's on us."
Greatwood oversees a group that features redshirt junior center Hronnis Grasu (6-foot-3, 297 pounds) and redshirt sophomore left tackle Tyler Johnstone (6-6, 277), two of the top blockers in the Pac-12 and potential candidates to declare early for the NFL draft.
With an improving Oregon State defense featuring defensive end Scott Crichton and a likely Pac-12 championship game appearance against Arizona State, UCLA or USC -- all featuring outstanding pass-rushers and elite defensive fronts -- ahead, Oregon will have to block better, whether or not Mariota is running the ball.
"I think as Marcus' mobility improves, too, that will help ease some things up," Greatwood said. "We've got to do our job. We've got to get our pads down low, we've got to finish, and we've got to make sure our assignments are correct."
For Grasu and Johnstone, they have to show they can handle the quality of players they would be facing on a weekly basis in the NFL. Paving the way for 2.5 yards per carry and allowing six tackles for loss against a gifted group of Stanford defensive linemen and linebackers doesn't leave a good impression -- one far worse than the Thursday night that seemingly sunk Mariota's Heisman hopes.