Moto2 rider Romano Fenati was sacked by his Marinelli Snipers Team on Monday for grabbing Italian rival Stefano Manzi's brake during the San Marino motorcycling Grand Prix.
The team said in a statement they were severing Fenati's contract "for his unsporting, dangerous and damaging conduct".
Both riders were competing at high speed around the Misano track on Sunday when 22-year-old Fenati, riding a Kalex, leaned over and pressed Manzi's brake lever. Manzi briefly lost his balance before regaining control of his Suter bike.
"The Marinelli Snipers Team shall terminate the contract with the rider Romano Fenati, from now on, for his unsporting, dangerous and damaging conduct for the image of all," a statement read.
"With extreme regret, we have to note that his irresponsible act endangered the life of another rider and can't be apologised for in any way.
"The rider, from this moment, will not participate in any more races with the Marinelli Snipers team.
"The team, Marinelli Cucine, Rivacold and all the other sponsors and the people that always supported him, apologised to all the World Championship fans."
Fenati's actions followed Manzi's attempt to overtake him a few laps earlier. The pair had made contact as Manzi overtook on the inside, with both riders running off the track, losing several positions and dropping out of the points.
"I don't know how I managed to stay up," said Manzi.
"It's difficult to forgive a gesture like that, where an opponent tries to kill a rival at over 200km per hour."
Fenati - a Moto2 rookie this year aboard a Marinelli Snipers-run Kalex bike - was black-flagged and disqualified after 23 laps for "irresponsible riding".
The FIM MotoGP stewards panel later banned him from the next two rances in Aragon, Spain on September 23 and Thailand on October 7 for having "deliberately attempted to cause danger to another rider".
It is not the first time the Italian rider has been embroiled in controversy. He was forced to apologise for kicking out at Finnish rider Niklas Ajo during the Moto3 warm-up at the 2015 Argentinian Grand Prix.
He was dropped for disciplinary reasons during the 2016 season by the Sky Racing Team VR46, owned by Italian motorcycling star Valentino Rossi.
Fenati is 19th in the Moto2 standings with 14 points.
Manzi was also penalised and will start six places back on the grid for the next Grand Prix, for forcing Fenati off the track, shortly before the latter's outburst, when both were fighting for 12th position.