If JR redshirts in 2018 as even he has said he expects to, he will have not played a live snap in almost two years when 2019 rolls around. I would think at that point, SR would have to be really stinking up the joint to lose the job. Just a hunch, but I think given the severity and timing of his injury, he's not coming in with the mindset that he either plays right away or walks. He seems like a pretty level guy, and backing up someone of SR's ability (if that ability translates to results) as a redshirt freshman isn't going to make him jump ship.