Australia all-rounder Shane Watson was left "shaken" after being struck in the head by a bouncer during training today.

The 33-year-old was practising in the nets at Melbourne Cricket Ground ahead of the Boxing Day Test with India when his helmet was hit by a bouncer from fast bowler James Pattinson.

Watson fell to the floor and then walked out of the nets to be assessed by doctors, and a spokesperson for Cricket Australia revealed that he was "shaken but otherwise okay".

Bouncers have been in the news for the wrong reasons recently after Australia batsman Phillip Hughes died having been struck on the neck by a ball during a Sheffield Shield match.

Watson was playing in that game, turning out for opponents New South Wales at the Sydney Cricket Ground.

Teammate Mitchell Starc also left the session early having been hit on the knee by a ball, leaving both as potential doubts for Friday's Test.

Australia currently lead the four-match series 2-0 and know that victory in the third Test would see them build an unassailable lead.