First I'll tell you why it happened.
Second I'll tell you how you can try to legitimately fix it.
Third I'll tell you how you can cheat the game to "fix" it. I highly recommend that you don't do this as it's cheap as hell, but it's your game so why should I care how you play it?
1. Play style has nothing to do with your playbook. It's all about stats. IE. a scrambler QB only cares about QB rushing yards, a pocket passer only cares about QB passing yards, and a balanced QB cares about the sum of both.
For your corner example, it's based on his type. Coverage guys only care about CB INTs, I believe hard hitters care about CB tackles (I'm not 100% sure on this), and balanced CBs care about the sum of both.
You can find out who wants what under the team pitches screen (or whatever it's called); the one that lists all of your school's pitches (IE. academic prestige, pro potential, etc). It tells you what stats you need for each type of player.
2. To fix this legitimately, get more of the stats you need. If it was a coverage CB, then get more picks by CBs. If it was a hard hitter, get more tackles (or whatever it is). etc.
3.