Fremantle youngster Anthony Morabito's left knee will require a second reconstruction in what is a devastating blow for the gifted midfielder.
The 20-year-old hasn't played since 2010 after rupturing the anterior cruciate ligament in the same knee late that year.
But Morabito had been well advanced on the comeback trail recently, having played regular footy with WAFL club Peel Thunder, and appeared to be edging closer to a senior recall.
However his hopes of donning the purple guernsey for the first time since the 2010 Second Semi-Final were dashed on Friday when he injured the knee at training.
And the former No.4 draft pick received confirmation from his specialist on Wednesday that he would have to undergo another reconstruction due to the damage which had again been caused to the anterior cruciate ligament in his left knee.
"It is bitterly disappointing for Anthony, his family, the club and our members and supporters," Fremantle football manager Chris Bond said.
"However, we see Anthony as having a long-term future with the club and remain confident that, with the appropriate recovery and rehabilitation program, he will return to senior football next year."
The latest blow caps of a frustrating two years for Morabito who burst on the scene in 2010, playing all but one of the Dockers' 24 matches in his debut year, including the club's third-ever finals series.