Parramatta co-captain Tim Mannah yesterday expressed his family's disappointment at reports linking his late brother Jon's cancer battle with alleged peptide use at Cronulla NRL club.
Tim said in a statement his brother would never have knowingly taken a banned substance.
Jon died from Hodgkin's lymphoma earlier this year, aged 23.
He had recovered from a first bout of the lymphoma in 2009 to play the first five NRL matches of 2011.
News Ltd newspapers yesterday published a leaked extract from an independent report commissioned by the Cronulla club into alleged use of peptides in the club's supplements program in 2011.
It questioned whether Jon Mannah's cancer relapse could be linked to peptide use.
In a statement issued by the Eels, Tim Mannah said his brother's integrity spoke for itself.
"On behalf of my family, I would like to say how disappointed we all are by the reports that have been published today," the statement read.
"My brother Johnny was a wonderful man and never, ever would have knowingly consented to taking a banned substance.
"In fact, he was very careful about everything he did that may affect his health.
"Johnny's integrity in the way he lived his life speaks for itself.
"We have no need to defend that."
Wests Tigers captain Robbie Farah says he feels sorry for Jon Mannah's family.
Farah took to Twitter to slam publication of the extract."Absolutely disgusted.. @dailytelegraph should hang their heads in shame. What a low, disrespectful piece of "journalism" in 2days paper!" he wrote.
He was more restrained but still critical when he fronted a Wests Tigers media conference at Campbelltown Sports Stadium shortly afterwards. "I think it's terrible for the family and for them having to go through that again," Farah said.
"I'm sure they're still having to deal with everything that's happened and losing Jon earlier in the year. So I just feel for the family."
The Sharks were implicated due to their connection with controversial sports scientist Stephen Dank, who worked briefly with the club in 2011.
New Sharks CEO Bruno Cullen told News Ltd the club had handed the report, compiled by ex-ASADA deputy chairwoman Tricia Kavanagh, over to ASADA and the NRL. But he would give no further details.
There has been no direct evidence that Mannah was given any supplements at Cronulla.
Dank has yet to comment on the report and it's not known whether the peptides mentioned were part of his programme at the club.
He has said he never gave banned drugs to players.
Leading sports physician Dr Peter Larkins has said it would be "absolutely indefensible" if Mannah, as a player with a cancer history, had been given a product that increased cell growth.