Callahan was named successor to the fired Frank Solich on Jan. 9. Pelini served as interim coach in a 17-3 win over Michigan State in the Alamo Bowl.
The lone survivor of Solich's staff is Turner Gill, a former Nebraska quarterback, who has been offered the position of receivers coach after serving as quarterbacks coach. Gill interviewed for the head job before Callahan was hired.
Also, Scott Downing will serve as recruiting coordinator and Dan McLaughlin has been asked to continue in his role as a graduate assistant. All three were on Nebraska's staff last season.
Callahan himself was fired as coach of the Oakland Raiders on Dec. 31.