I thought third was dismissal??
I decided to look it up. The link attached is the UT Student Athlete Handbook. Page 55 starts with positive tests and the levels.
It isn't a black and white rule as the AD (and I assume, head coach) has some discretion. I always thought at least the first positive test (of marijuana) just required counseling, and that is correct. It does look like a suspension occurs after the second positive test, but it's determined by the AD. The fourth positive tests results in permanent suspension.
http://grfx.cstv.com/photos/schools/tenn/genrel/auto_pdf/compliance-handbook.pdf