Telling Tom Osborne “no” was one of the most difficult decisions Tim Cassidy said he’s ever had to make.

Yet that’s what Cassidy did Friday, when he told Osborne he’s resigning as Nebraska’s associate athletic director for football and taking a similar position at Texas A&M.

“He was extremely gracious and generous,” Cassidy said of Osborne, Nebraska’s interim athletic director. “Sometimes you just have to make a decision that you feel like that’s the right thing to do.”

Cassidy, who’s close friends with newly-hired Texas A&M football coach Mike Sherman, begins his new job today.

Cassidy, an Omaha native, spent 19 years at Texas A&M and worked with Sherman for seven years before Sherman left for the NFL in 1996.

In Lincoln, Cassidy worked in football operations with football coach Bill Callahan and athletic director Steve Pederson, both of whom were fired this fall. Cassidy said his decision to leave had nothing to do with the hiring of a new football coach at Nebraska.

“A&M is the only place I would’ve left for,” Cassidy said. “It could’ve been Ohio State or Oklahoma, and it wouldn’t have made a difference.

“Coach Osborne was phenomenal. I always wanted to work for Nebraska, and particularly a chance to work for him. I didn’t know it was going to be for only six weeks.”

Cassidy is a 1981 Nebraska-Omaha graduate. He received his master’s degree in education from Texas A&M in 1984. While with the Aggies, he was a graduate assistant coach, recruiting coordinator and eventually associate athletic director for football before leaving for Nebraska in 2004.

His son, Austin, was a walk-on freshman this past season and will remain with the Huskers, his father said.

“Things will go well (at Nebraska),” he said. “With Coach Osborne embracing the program, I’m certain he’s going to hire a good, quality person. I’ve assured him that I would do everything I could to help Nebraska in anyway I could.”

Reach Brian Rosenthal at 473-7436 or brosenthal@journalstar.com.