HIGHLY touted Greater Western Sydney youngster Paul Ahern looks set to miss the entire 2016 season after rupturing an anterior cruciate ligament at training on Monday morning.

The promising 19-year-old midfielder, who was the No.7 in the 2014 NAB AFL Draft, will undergo a reconstruction of his right knee after scans confirmed the club's worst fears.

It was a cruel blow for Ahern, a former Calder Cannons player and All Australian under-18 star, who had made good strides in his development this pre-season after last year producing solid football for the Giants' reserves in the NEAFL in his first season at the club.

GWS head of athletic performance David Joyce said Ahern would meet with a knee specialist this week.

"We’re all really disappointed for Paul, who’s had a great pre-season and was progressing really well," Joyce said.

"We’ve got Paul’s long-term welfare as our first thought so we'll now look to determine the best course of action to ensure he can return stronger than ever."

Ahern has yet to play a senior game for the club.