Bellator MMA officials announced the event on Friday. The live card will take place at Pechanga Resort and Casino and air on Spike TV.
Straus (22-5) forfeited the Bellator 145-pound title in March in a submission loss to Pat Curran in Hammond, Indiana. Before the loss, Straus had won six fight in a row, including a unanimous decision over Curran that won him the title in November.
"I'm ready to get back to work," Straus said in a statement. "I love to stay active, fight as much as I can, and now I have the opportunity to get back on the road to getting my title shot."
Wilcox (14-6) is coming off a unanimous decision win over Jason Fischer at Bellator 114 in March. The 35-year-old veteran is 3-1 since signing with Bellator last year.
The winner could position himself to fight for the title next. Curran (20-5) will seek to defend the belt against Patricio Freire (21-2) on Sept. 5.