Here was my Tale of the Tape on Thomas ...
Pros: Thomas has the ball instincts, speed and agility to be an NFL cornerback, and some teams might try to switch him depending on scheme. Excellent deep backpedal and turn into center coverage. Will close on receivers in a hurry and has a great sense of position on intermediate-to-deep routes. Good jump and burst to the ball when playing underneath routes or closer to the line. Doesn't simply key on his first read through the play; has a real eye for the ball and an ability to change direction and coverage very quickly. Excellent straight-line speed to rush the passer in a blitz, but will be negated if he has to deal with too many blockers. Will bait quarterbacks and jump routes with the best of them. Is just as effective in a pass defense playing at linebacker depth as he is playing deep thirds.
Cons: Not a great tackler, with plenty of evidence on film to support that assertion. Will occasionally bite on backfield misdirection. Not yet fluid in man coverage, which is probably just a teaching point as opposed to a physical flaw, because he has the speed to get wherever he wants to go. Doesn't get off blocks very well and has trouble in run support despite a willingness to sacrifice his body.
Conclusion: Thomas will probably be best at his best with a team that has definite free and strong safety designations, or in schemes in which safeties are asked to play more coverage. He is not an all-purpose safety in the traditional sense; he isn't physical like Troy Polamalu(notes), Ronnie Lott, or Ed Reed(notes). He is more a pass-coverage safety in the mold of a Darren Sharper(notes) or Jairus Byrd(notes). But as we have detailed, these kinds of safeties are more important to the pro game than they've ever been, a fact that could find Thomas as a surprise top-15 pick on draft day.
Pro Comparison: Jairus Byrd, Buffalo Bills