Milford, the former Brisbane five-eighth, has played seven games for the Knights since linking with them mid-season.

The Dolphins confirmed on Friday that the 28-year-old would reunite with coach Wayne Bennett for the club's foundation season.

Given that the Knights are effectively dead and buried in the finals race, there would appear some logic in reinstating Jake Clifford, who is contracted to Newcastle next season, at five-eighth.

But O'Brien said his priority was Newcastle's next game, at home to the Roosters on Friday night, regardless of what might transpire next year.

"I understand and respect Anthony's decision," O'Brien said.

"He's got a young family and a lot of their support network is back in Brisbane.

"Everybody understands the situation he finds himself in.

"But as I said in the press conference last week, I'm just focused on getting the team better each week, so I'm not looking at a long-term thing.

"So for us to get better this week, I want to have Anthony in the team."

Asked about Clifford, who has played only two NRL games since Milford's arrival, O'Brien replied: "I won't make change just for the sake of it. I think you have to earn the jersey ... the moment you just hand jerseys away, that haven't been earned, then you're under-valuing what it means to play in the jumper in the first place.

"So the No.1 thing for me is guys that are playing in the NSW Cup need to earn the right, regardless of the situation."

Meanwhile, Luke Keary will make his return for the Roosters on Friday after a four-week concussion-enforced lay-off.

Keary replaces Joey Manu in the halves and will resume his partnership with Sam Walker.

"He was pretty keen on playing last week," Roosters coach Trent Robinson said.

"We felt like he just needed a bit more training after a few weeks off.

"He's worked his way back into contact over the last few weeks."

Manu, who has usually played as a centre under Robinson, has been a revelation wearing the No. 6 jersey the last fortnight, scoring two tries and setting up three others.

He was also devastating in New Zealand's recent Test win over Tonga while playing as a fullback.

Robinson said Manu would be given the licence to roam around the field and get his hands on the ball more often.

"We've got Sammy Walker and Luke Kerry and I feel that it's strange that they are questioning their quality as players," Robinson said.

"Joey will also have the ability to play a certain style which will suit him.

"We've experimented with it over the last few years so he'll get his time on the ball."

The Roosters will also bring Jared Waerea-Hargreaves, who hasn't played since round 12, back from a hamstring injury.

The ninth-placed Roosters have lost Sitil Tupouniua and Billy Smith to season-ending knee injuries and travel to Newcastle knowing they need to win to keep pace with the NRL's top eight.

O'Brien said back-rower Tyson Frizell (ribs) and winger Edrick Lee (foot) would both play, although English winger Dominic Young won't be passed fit as he deals with a rib complaint.