Nicolo Bulega will sit out the United States round in Moto2 to undergo surgery to relieve severe arm pump, while Sky Racing VR46 has opted not to call on a replacement rider.

The Moto2 rookie was forced to retire from the Argentina race with five laps to go due to arm pump in his right forearm.

After flying back home to Italy to undergone medical checks, Bulega’s team has confirmed he will undergo surgery next Tuesday which rules him out of the next round at the Circuit of the Americas.

The 19-year-old, who has retired from both rounds of his rookie Moto2 campaign so far, is expected to recover at home and return to action at the Spanish round when the championship heads to Jerez on May 3-5.

Sky Racing VR46 also confirmed a replacement rider won’t be called upon for COTA, meaning Luca Marini will act as a sole rider for the squad in the US.

Bulega stepped up from Moto3 with Sky Racing VR46 this year after three campaigns in the lightweight class.

The Grand Prix of the Americas takes place at COTA on April 12-14.