Rolfo broke his left collarbone during a mountain bike accident last weekend and was initially expected to be replaced by Italian veteran Bussei.
However, Bussei had injured his right arm in a Supermoto accident three weeks' ago and, after trying to ride earlier this week, it was claimed that he was not fit enough to campaign the Hannspree Honda Althea CBR1000RR.
That led to AMA star Zemke being approached for the ride, which he apparently accepted. However, it soon proved logistically impossible for the 32-year-old to make the event and, following a medical check, Bussei has now been cleared to participate.
35-year-old former Italian Superbike Champion has taken part in 112 WSBK races, including four races for Sterilgarda Ducati last season, but never claimed a podium finish.