LUBBOCK, Texas -- Texas Tech quarterback Taylor Potts did not return after halftime following two sacks by New Mexico late in the second quarter.
Tech trainers checked Potts' balance -- he stood on one foot and then the other -- and rubbed the back of his neck.
Lobos linebacker Carmen Messina sacked Potts on a first-down play and Johnathan Rainey threw him to the ground on third-and-9 after Potts scrambled toward the far sideline.
The nation's leading passer got up slowly, stood still momentarily as he bent over, resting his hands on his knees. His head was down as he made his way to Texas Tech's sideline
Backup Steven Sheffield replaced Potts and led the Red Raiders on an 86-yard drive to a touchdown, hitting Alex Torres for a 25-yard score with 1 second remaining in the half for a 14-7 lead.