Scotsman Billy Mackenzie will replace Aussie Chad Reed at Monster Kawasaki for the final two AMA rounds.

Current Australian MX Nationals number two Billy Mackenzie is set to make a shock appearance in the final two rounds of the 2010 AMA Motocross Championship onboard Chad Reed’s factory Monster Energy Kawasaki.

According to sources, the Scotsman and former World Motocross Championship race winner will jet out to the United States tomorrow to complete a week of testing with the U.S. team before making his race debut at the Steel City National in Pennsylvania on Saturday, 4 September.

Mackenzie has been a standout in the Pro Open class of this year’s Australian Motocross Championship with the Troy Carroll-managed Kawasaki Racing Team, finishing second to three-time champion Jay Marmont despite suffering a severe wrist injury at Canberra’s second round.

Yet to be announced by Kawasaki, it’s expected that Mackenzie will replace Reed for the final two rounds of the American series, since Australia’s current AMA champion Reed has been ruled out with Epstein Barr virus.

Following the Steel City National, Mackenzie will then join the team to round out the season at Pala Raceway’s season finale in California.

Mackenzie was originally requested to compete at Southwick this weekend, however due to a lack of testing and minimal riding since the MX Nationals season finished at Coolum late last month, it was decided for Mackenzie to wait an extra week for his AMA debut this season.