Edgar's first fight at 135 pounds will serve as the co-main event at UFC Fight Night on Jan. 25. The card will take place at PNC Arena in Raleigh, North Carolina, and air on ESPN+.
Edgar (23-7-1) won the UFC's 155-pound championship in 2010, and recorded two successful title defenses before losing the belt to Benson Henderson in 2012. The New Jersey native dropped to 145 pounds in 2013 and fought for the featherweight title three times, coming up short in each. He lost to former champion Jose Aldo twice and current titleholder Max Holloway once.
There has been intrigue in Edgar competing at 135 pounds for years, as the 38-year-old never has cut a significant amount of weight during his career.
Sandhagen (12-1) is one of the most promising young title contenders at bantamweight. The 27-year-old is 5-0 since signing with the UFC in 2018, and has defeated established veterans Iuri Alcantara, John Lineker and Raphael Assuncao, among others.
Fighting out of Denver, Sandhagen has finished three of his five bouts in the UFC.