Hardaker has missed the last two matches due to an ankle problem suffered in a man-of-the-match display against Wigan Warriors at Magic Weekend.
Young stand-off Liam Sutcliffe has switched to the No1 role to fill the void in the last couple of games with mixed results.
However, the crocked star should be named in Brian McDermott’s 19-man squad later today and then hopes to get through tomorrow’s final session in readiness for Hull’s arrival at Headingley on Sunday.
“We could possibly have Zak back this week,” said the Rhinos boss yesterday. “Usually with that type of ankle injury you get some quick gains and then it plateaus out with small incremental gains before getting back to full fitness and he is now at that latter stage.
“Joel Moon with his Achilles injury is in a similar position as is Brett Delaney and all three will be a late call this week.
“Jamie Jones-Buchanan is a couple of weeks off and Tom Briscoe is still a number of weeks away whilst Mitch Achurch has about ten weeks to go.”
The news on Briscoe is a blow given Leeds were planning on having the 25-year-old – out since March 13 with a shoulder injury – back in their ranks imminently.
McDermott explained: “We originally hoped Tom would be back for the Cup game next Friday but that is looking unlikely.
“We want them all to play but there is still a fair old chunk of the season to go and making emotional or irrational decisions at this time of the year will hurt us in the long run.”
Briscoe, in his second season since moving from Hull, scored four tries in the opening five games this year but youngster Ash Handley has made a fine impact of his own having been blooded in the side since his colleague’s injury.
Hull boss Lee Radford has some selection issues of his own with ex-Great Britain centre Kirk Yeaman a doubt.
But he can recall prolific Tom Lineham, who recently announced a £140,000 move to Warrington Wolves for 2016, and fellow winger Curtis Naughton.
Radford said: “Kirk is struggling with his ankle this week, so we’ll give him a late fitness test. But in terms of injuries we’re doing really well and it’s a credit to all of the staff.
“Tom will be in contention for selection and Curtis too.
“He got through 80 minutes at Doncaster for us which was great, alongside Josh Bowden.
“Dean Hadley will play there Friday night (versus Featherstone), so we’re not far off having a full-strength squad which I think is important with the congestion of games coming up.
“James Cunningham picked up a knock a few weeks ago playing for Doncaster so he is no good.”
Radford – whose Hull side have a rearranged midweek game with Wakefield Trinity after the Cup contest – continued: “I would have liked to have mixed the side up this weekend.
“That’s changed slightly. That will be disappointing for those blokes, I suppose, but we’ve known about this schedule for a while and we’ve prepared as best as we can in terms of recovery and having the extra strength in that department.
“It’s going to be challenging but critical too.”