MotoGP rookie and reigning Moto2 champion Pol Espargaro faces a fight to regain full fitness for the opening race after breaking his left collarbone on the final night of pre-season testing.

The Monster Yamaha Tech 3 rider, set to finish tonight's Qatar test a close second fastest to older brother Aleix, is expected to undergo surgery on Monday.

The Qatar Grand Prix takes place at the same Losail circuit from March 20-23.

Espargaro joins reigning MotoGP champion Marc Marquez on the injury list. Marquez has missed two pre-season tests due to a leg fracture.