The 33-year-old was left shaken by the fierce blow to the head and he left the MCG nets following the incident that put an early end to Australia's training session before the Boxing Day Test.
Pattinson too looked distressed as he also walked out of the nets even as players and officials walked up to Watson to check on him.
Watson was hit on the helmet when he tried to dodge the bouncer. The impact caused Watson to fall to his knees as removed his helmet, inspected it and then walked off the nets.
A Cricket Australia spokesperson said the dazed Watson was shaken but otherwise okay after and vice-captain Brad Haddin later confirmed his teammate had escaped unscathed.
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"I had a chat to him - he's a bit shaken, but he's ok," Haddin said.
Haddin didn't want to read too much into the incident.
"It's just getting hit in the head - he's just a bit shaken," he said.
"He's shaken as anyone would be. I can't really go into any more details because there's no more details to give."
The incident brought back tragic memories of Hughes' death, which the Australian cricketers are still battling, more than two weeks after the young batsman had fallen to a fatal bouncer during a Sheffield Shield game.
Earlier, Mitchell Starc too seemed to hurt his knee while batting in the nets alongside Watson. It seemed Starc inside edged a delivery from a net bowler onto his knee, and yelled in pain.