'Mental stamina' key for coach Derek Dooley

photo University of Tennessee football coach Derek Dooley speaks to the press during an event.

KNOXVILLE -- The good was the offense's ability to convert in key moments, but the bad was the defense's inability to get off the field.

The dueling sides of the third-down story was a theme in Tennessee's third camp scrimmage Saturday, and coach Derek Dooley already found a reason for his defense's struggles to get off the field.

"The mental stamina," he said after practice Monday morning. "What happens is you're playing good, you're making the right checks, adjusting to the formations, and then about the sixth or seventh play of the drive, fatigue sets in and now all of a sudden you're not thinking clearly.