His fight against late replacement Rodrigo Damm (8-2) will be for the interim Strikeforce lightweight title.
Melendez, the previous titleholder, lost to Josh "The Punk" Thomson (16-2) last June via unanimous decision.
Damm last June defeated Jorge Masvidal via TKO at Sengoku in Japan.
The current champ was slated to give Melendez a rematch for the belt at the April 11 event but pulled out on April 1 due to a broken left leg from sparring. Thomson said he hopes to be back from surgery in five to six weeks.
- Frank Shamrock (23-9-2) vs. Nick Diaz (18-7)
- Gilbert Melendez (14-2) vs. Rodrigo Damm (8-2)
- Scott Smith (14-5) vs. Benji Radach (19-4)
- Cris "Cyborg" Santos (6-1) vs. Hitomi Akano (14-5)
- Brett Rogers (8-0) vs. Ron "Abongo" Humphrey (12-0)
- Luke Rockhold (3-1) vs. Buck Meredith (3-2)
- Eric Lawson (8-2) vs. Waylon Kennell (4-1)
- Raul Castillo (5-0) vs. Brandon Michaels (1-2)
- James Terry (5-1) vs. Zak Bucia (1-1)
- Jeremy Tavares (0-3) vs. Shingo Kohara (0-0)