(STATS) - Southern Utah football's success this season has helped cost the Thunderbirds their head coach.

Ed Lamb resigned Saturday after eight seasons at Southern Utah to return to Brigham Young, his alma mater, and become a member of new coach Kalani Sitake's staff. He will over oversee the Cougars' tight ends and special teams.

Lamb posted a 45-47 record at Southern Utah, winning the Big Sky Conference title this season as well as a Great West Conference championship in 2010. He led the Thunderbirds to their first two FCS playoff appearances in 2013 (8-5 record) and this season (8-4).

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At BYU, Lamb played defensive end in 1995 and '96, and he served as a graduate assistant coach in 2001.

"I'm excited to get back to BYU, a place that has been very instrumental in my life," he said. "My time on campus as a Cougar changed my life, and continues to shape who I am today."

Said Southern Utah athletic director Jason Butikofer: "Coach Lamb has taken this program to unprecedented heights, culminating with our first-ever Big Sky championship this fall. He has meant a great deal to Southern Utah University and the Cedar City community. We truly appreciate his efforts in raising the stature of the Southern Utah athletic department. With the foundation that Coach Lamb built, there will be great interest in this leadership role and I am confident that we will find a head coach that will continue to elevate our football program to new heights."

Defensive coordinator Demario Warren was named Southern Utah's interim head coach while the school undergoes a national search for its next head coach.