Kentucky's rushing defense ranks 12th in the SEC, giving up 195.9 yards per game. Bama's rushing defense is 1st in the SEC, giving up 64.6 per game.
Now, if he were to go off for 200 against Bama's D, then he'd get a lot of attention nationally, but still not Heisman talk. With 5 losses already, you won't have a player in New York, even if you won out and he gained 1000 yards over his last 3 games. That's just the way the Heisman works. It's a team award for the most part. The last player to win it from a team with more than 3 losses was Ricky Williams, and rarely do you even have a player get an invite or finish Top 5 if his team has more than 3 losses.