Erion Honda’s Jake Zemke and Monster Energy Attack Kawasaki’s Jamie Hacking may race in the Superbike World Championship event May 29-31 at Miller Motorsports Park, in Tooele, Utah. Zemke, who just returned Wednesday from Monza where he filled in for Stiggy Racing Honda’s injured John Hopkins, may fill in again at Miller if Hopkins (who suffered a broke hip and femur in a crash during practice at Assen) is unable to ride. “Obviously, it’s all up to John,” said Zemke. “It’s his bike to ride. I’m just filling in. If he’s not able to ride, I’ll be ready to go. I’m just kind of on hold at the moment.” Hacking is being considered as a substitute for Kawasaki factory rider Makoto Tamada (who broke his wrist in a Turn One crash at Monza) at the Miller Motorsports Park event. “There’s a possibility I might do it,” Hacking told Roadracingworld.com Thursday night at Infineon Raceway. For this weekend’s World Superbike event at Kyalami, in South Africa, Tamada’s seat is being filled by Sheridan Morais, a Kawasaki racer and the defending South African Superbike Champion.