Walker has been missing for an extended period, having originally been cut from the Roosters' best 17 ahead of Anzac Day.
He then injured his knee and, while the return timeline was originally set at just a matter of weeks, has only returned through the NSW Cup in recent times.
While the Roosters are keen to get him back into their underperforming 17 as they cling onto an increasingly unlikely chance of making the top eight, the coach told the media on Thursday that Walker was no chance of returning for the game, with the Roosters as stable as they have been all year in recent times.
"We are probably as stable as we have been almost all year," Robsinon said.
"We have had consistency especially in our backline and even in our forward pack being able to pick similar teams week on week which we haven't this year.
"Sam, he came back and trained last week, so that decision about whether to play him or not. We needed another week from him playing, but he is getting close. He is getting back to almost full training with us so we will get there over the next week.
"No. He had a good outing there last week, but he has had four months out and then he trained last week fully, and then he trained part of Wednesday's session. It is just getting time on legs with him and getting to the point because we need to nail it on Sunday to the point where he is fully ready to get back into the NRL.
"That's not going to happen this week."
Walker, who played in the 25 jersey for the North Sydney Bears against the Roosters in the reserve grade competition last weekend, managed the full 80 minutes in a performance which saw him run 135 metres and lay on two try assists.
He has not been named for the Bears this weekend, but is likely to be a late inclusion for their clash with the Penrith Panthers on Sunday afternoon at North Sydney Oval.
Robinson re-affirmed the club's commitment to Walker though, following speculation earlier this year that he may ultimately leave the club after his axing from first-grade.
The coach said Walker was part of the long-term plans for the Roosters despite his lack of action this year.