First, let's focus on the gimmie throws the Gamecocks intentionally set up. A perfect example of their desire to get the ball out of Shaw's hands through sure passes to let TEs and backs make short pass completions and turn them into decent gains can be seen in the Missouri game. Shaw was 20/21 in that football game with his lone incompletion coming on his first pass attempt of the football game. The video below shows all of his pass attempts in that game. Notice he only threw the ball 10+ yards approximately three times all game. All the other passes were baby hooks, screens, or basically flairs to the backs.
Along those same lines, a lot of people probably don't realize this, but Marcus Lattimore led South Carolina in receptions prior to his injury. Likewise, I expect Scar to continue getting their backs involved in the passing game even without Lattimore. Against Arkansas, Kenny Miles recorded three of the 15 catches for the team. These three catches went for 44 total yards.
Scar likes to put their backs in the flats and use them to run arrow to hook routes and get these guys 5-8 yards downfield but in the middle of the playing field. Occasionally, they will streak a back down the field either up the seam and have the potential to go deep here off of wheel type routes if the defense is overly aggressive. Keep the last sentence of info in your back pocket but understand that Carolina has been most successful using backs in the passing game by getting them the football around the LOS but in space and letting these guys run after the catch.
Keeping with the ball control theme, Justice Cunningham is a very capable tight end and South Carolina likes to use him to methodically pick up yardage through simple, short routes. One of their favorites is the 5-8 yard hook route. They will run him on short dig/crossing routes. Another nicely drawn up scheme crosses him with another TE/WR to pick up an easy 4-5 yards prior to contact.
He does a good job getting down the field, finding open spots and rolling with the quarterback when Shaw is forced to scramble. The other obvious downfield routes occur when there is a mismatch with Cunningham splitting the seam and using his size in the passing game or, because of his size, running a dig or post to provide a big dependable target over the middle. Cunningham is a tough guy and can definitely take/deliver a shot.
Scar has capable receivers, though their main receivers do lack size. This means that any pass downfield must be throw with precision and accuracy. Ace Sanders and Bruce Ellington have been the consistent "go to" receivers. Each is extremely explosive and dangerous in open space. All the Scar receivers run good routes--short, intermediate, and long--which could give our Tigers problems. These guys have speed as well, which was on display last season in Clemson's game against Scar.
We'll see a little of everything with the Gamecocks emphasizing a layered approach. They will assure at least one eligible player runs a shot, medium, and long route. Underneath, Carolina will drag receivers across the field--especially on crossing routes. They will also use a variety of wide receiver screens. The medium routes they like include basic dig, stop, and hook routes. They will streak receivers down the field (both over the middle of the field and down the sidelines) and get their guys to the post, but what the Gamecocks really like to do down the field is run simple corner/flag routes that may or may not be a part of a double move (i.e., post-corner).
The final element of the Scar passing attack doesn't involve passing the football...it revolves around quarterback Conner Shaw being forced out of the pocket and/or the defense's inability to maintain containment. Shaw is a slippery quarterback who is very capable of picking up yardage on the ground. He is also very capable of completing passes while scrambling around. Long and short, this is a guy who will get mobile if his initial reads/progressions are not obviously open. When he gets mobile, defenses this season have paid.
The South Carolina offensive line is less impressive than it has been the past couple seasons. Tennessee and others were effective getting pressure on the Carolina signal caller. I don't think that it is impossible for Clemson to apply pressure considering this line is penetrable and Scar will have less experience in the backfield to help with blitz protection. How well Clemson gets to Shaw AND contains him will likely tell the playcalling tale.
Fortunately, if Clemson can force Scar to become a predominantly passing team, the odds go way up in Clemson's favor despite some of the issues our Tigers have had defending the forward pass this season.