Officials announced the bout Friday night during the broadcast of Bellator 193.
Primus (8-0) won the title this past June at Bellator: NYC when the doctor at cageside stopped the bout due to several vicious leg kicks landed. He signed with Bellator in 2013 and has won six times.
Chandler (17-4) solidified his status as the No. 1 contender with a decision win earlier this month over Goiti Yamauchi. The former champion is now 5-1 over his last six.
Bellator 196 goes down April 13 from the Family Arena in St. Charles, Missouri.