The two V8 Supercars stars were expected to line-up as co-drivers for the category's Taupo, Pukekohe and Ruapuna events, but have now alerted their respective fans via social media that they won't be competing.
Speedcafe.com understands that the announcements have come following a recent briefing to the V8 Supercars teams by chairman Tony Cochrane in which they were strongly discouraged from allowing their drivers to take part in the domestic series.
V8 SuperTourers provided a brief statement distancing itself from the issue when contacted by Speedcafe.com.
“What happens between V8 Supercars, its teams and its drivers is a matter for them, not us,” read the statement.
“If that means some drivers that might otherwise be interested in competing over here do not, that might be disappointing, but that's life.”
V8 Supercars also provided Speedcafe.com with a statement when asked for its official position on the matter.
“If a driver commits to a full-time, professional career with a team in the category, V8 Supercars would prefer that it is their complete focus, on and off the track,” read the statement.
“This is in line with all elite sporting bodies where, as a general rule, athletes do not compete in other codes or competitions, particularly during the primary season of competition.
“Of course there may be some limited exceptions which would be a discussion between the driver and their respective team.”
Greg Murphy, who had been competing full-time in both series prior to his current injury-induced layoff, says he still expects to drive in the remaining SuperTourer events.
“I've been committed from the start to run the whole series and nothing has changed,” Murphy told Speedcafe.com.
“It's disappointing that I've lost Fabian as a co-driver but that's the way it goes.
“At the end of the day V8 Supercars is a much bigger fish than what we are. We need to respect their decisions and what they're trying to do.”
Despite the developments, it is understood that Murphy will be joined on the Taupo grid by two other full-time V8 Supercars drivers, the first of whom is set to be confirmed tomorrow morning.