I think Gaulden's loss will be felt more heavily in the Oklahoma game than probably any other of the year (short of going to Atlanta).
Oklahoma has a talented passing QB, with talented WRs as targets, and a solid pass pro O-Line. That is more than can be said about most (any?) of our other 2015 foes. Half of them are still picking out a QB from among less-than-inspiring options. Some of them have one significant WR, and that's it, everyone else is utterly unproven. With a QB that can easily be flustered by our DLine, and/or a single threatening WR that we can lock Cam onto, well, the bulk of our time can be spent countering the run game. Because they won't have much success passing.
That's not true of Oklahoma. They have the elements they need, including multiple proven and promising WR targets: Sterling Shepard is an all-american, their alpha male WR, but they also have Neal, and Young, and Quick, and a JUCO named Westbrook who's supposed to be hot, and a 4* freshman named Andrews who might contribute from the start of the year ... in fact, I think it's fair to compare their stable of WRs with our own. Many lucrative targets for this new, touted gunslinger QB Baker Mayfield to look for.
Bottom line is, yep, if there's a single game we could most use Rashaan's talents in, this would be the one. It does indeed hurt to lose him.