LINCOLN, Neb. -- Quarterback Tommy Armstrong Jr. continues to struggle with a hamstring injury and did not practice Friday as No. 24 Nebraska began preparations for the Franklin American Mortgage Music City Bowl against Tennessee on Dec. 30.

Coach Mike Riley said he's preparing fifth-year senior Ryker Fyfe as if he'll be the starter, with Zack Darlington as the backup.

Armstrong, a four-year starter, injured his hamstring in the second half against Minnesota on Nov. 12. Fyfe started against Maryland, and Armstrong returned for the 40-10 loss at Iowa on Nov. 25.

Riley said it was "courageous" for Armstrong to play against the Hawkeyes, but there has been a setback in the healing of the hamstring.