Cardale discussed the QB controversy and how it affected his play. He was under the assumption that once a starter was named that person would be the starter from there on out without a short leash put on them. He didn't expect a back and forth thing to continue throughout the season.
http://theozone.net/Ohio-State/Football/2015/News/Cardale-Jones-Spent-2015-Looking-Over-His-Shoulder
IMO, this was the single thing that affected both QB's this year. The play calling wasn't good, but neither had an opportunity to get in a rhythm all year. Cardale got yanked after a few mistakes, and JT came in and tried to do too much to ensure he overtook the job.