They join the staff to replace defensive coordinator, linebackers coach Mike Cox, and secondary/safeties coach Jeff Mills who were all fired following the Alamo Bowl.
Before joining Tennessee in 2010, Wilcox served as the defensive coordinator at Boise State and as linebacker coach at Cal before that. Wilcox had been under consideration for the Florida Gators head coaching job last year.
Sirmon played linebacker for the Tennessee Titans for seven years before joining the Oregon Ducks in 2009 as a graduate assistant. He came to Tennessee in 2010 as a grad assistant working under Wilcox and is considered one of the top recruiters in the south. He is a Washington native.
Wilcox and Sirmon were teammates at Oregon together during their playing days.