Flanagan and Xerri have been best mates since childhood, having played together from a young age at the Aquinas Colts right through to Cronulla in the NRL last year.

They also spent part of the coronavirus shutdown training together at sprint camps, despite Flanagan's off-season move to Sydney Roosters.

Flanagan said on Friday night he had reached out to his former Sharks teammate given their close relationship, but had not spoken to him properly.

"I'm shattered and still in shock," Flanagan said.

"I don't want to comment on it too much because I will let him do his thing.

"I haven't had any contact with him. I tried to reach out with some support as a mate.

"But I know my focus is on the Roosters and bring success to the Roosters.

"But yeah, I'm shattered."

Flanagan made an "X" mark with his arms after he scored in the Roosters' win over South Sydney on Friday night, in a symbol many took as a show of support for Xerri.

There had been every chance the pair could reunite at the Roosters in coming seasons, after Xerri knocked back a five-year deal at the Sharks.

Flanagan showed no signs of the disruptive week in Friday's win, as his combination with James Tedesco and Luke Keary continued to gel.

But for now, Xerri's future looks far more bleak, with a possible four-year ban hanging over his head if found guilty.

He remains provisionally stood down as ASADA continue their investigations into a cocktail of banned substances found in his system last November.

The results of the B-sample will likely take weeks, while the star centre's phone was initially seized but has since been returned.

Meanwhile the NRL have now confirmed they are satisfied with ASADA's reasoning of why it took six months to notify them and Xerri about the positive test.

Xerri was only told on Tuesday that he would be provisionally suspended, just two days before the season's resumption.

The issue prompted questions from several current and former players, as the NRL also contacted the doping agency over the delay.

They were notably puzzled following the fast turnaround to stand down James Segeyaro during last year's finals after a positive test for Ligandrol last year.

But interim NRL chief executive Andrew Abdo said he had heard back from the agency and was satisfied with the explanation.

"ASADA is an independent organisation. We have written to them and asked to understand the process and time it has taken," Abdo told Triple M.

"They have responded and we are satisfied with the response we have received.

"But obviously this is a difficult time for Bronson.

"It was just an understanding of the process that was taking place. It's obviously a really sensitive matter and not something we can talk about."

Australian Associated Press