The veteran Australian was set to race with the team until the Monza round in May, but was informed earlier this week by the Italian squad that they could no longer run him.
It is the second time Martin – who lies 17th in the championship – has been dumped by the team, although when the news came before Donington Park, he managed to scrape together enough money to keep going for two more rounds.
Martin, 38, has wasted no time in sorting himself out a new ride, joining the Yamaha Germany team in the World Supersports Championship as a substitute for his injured countryman Kevin Curtain.
Martin said: "I can't believe the way this all came about really, but when Kev asked me personally to fill in for him I was in shock as it was the last phone call I was expecting.
"No one likes to fill in under these circumstances, especially when it's for one of your mates, but I will do the best job possible to help Kev, his team-mate Brock [Parkes] and Yamaha."
DFX, meanwhile, will run just one bike in this weekend's Assen double-header in the Netherlands, for Michel Fabrizio, whose programme is financed by Honda.
EuroSport
Subject: DFX drop Martin...again 
Thu Apr 26, 2007 1:33 pm