Gresini Racing has withdrawn its MotoGP and Moto2 teams from the season-ending races at Valencia following the death of Marco Simoncelli in Sunday's Malaysian Grand Prix.
Team boss Fausto Gresini also confirmed his riders would miss the end-of-season tests which follow on from the November 6 races.
"The only certainty is that my team won't participate in the upcoming Valencia Grand Prix and in the tests programmed after the race," Gresini told Corriere dello Sport.
The 24-year-old Simoncelli died in Sepang after losing control of his Honda at turn 11 and swerving across the track, straight into the path of American rider Colin Edwards and his fellow Italian Valentino Rossi.
Simoncelli, who had joined Gresini for his first season of MotoGP in 2010, suffered fatal injuries to his chest, neck and head during the crash.
Gresini said: "Everything happened so fast. I'm lost for words.
"I know our job is dangerous, that risk is part of the game, but you always hope nothing happens.
"When it does happen and you find yourself in the middle of it, everything changes, it's difficult to accept it.
"The crash was caused by a sequence of incredibly negative circumstances, the bike that moved towards the inside of the turn instead of the outside, being run over on the widest track of the season."
Gresini paid tribute to Simoncelli, who will be laid to rest in his home town of Coriano on Thursday.
"I have many images from these two years spent together resurfacing inside my mind," he said.
"Marco was spontaneous, he would always do what he thought, with a great heart and always radiant. I can't remember him getting angry even once.
"He was always honest with himself and with the others, a guy who loved challenges, and we, his team, were just an instrument to realise his dreams and to unleash his passion."
- More about: