With an extending injury list now including props Eamon O'Carroll and Chris Green, Gentlewill give a debut to new signing Jay Pitts.
And such is the crisis amongst the forwards that Lee Radford has been asked to come out of retirement to take on the old enemy. Full-back Wade McKinnon has been included in the squad after being sidelined with a groin injury, while Kirk Yeaman takes the place of the injured Tony Martin.
Centre Yeaman was included last week after recovering from a foot operation but although he didn't feature in the game against Bradford is expected to start this time.
Hull KR boss Craig Sandercock could name his strongest side since taking over in charge after including both skipper Ben Galea and stand-off Blake Green.
Neither has played this season but are both likely to enjoy some game time at the KC. Utility back Craig Hall is also poised to return with Jordan Cox, Liam Salter and Sam Latus all missing out this week.
Hull squad: Aspinwall, Bowden, T. Briscoe, Ellis, Horne, Houghton, Kent, Lynch, Manu, McKinnon, Nicklas, Pitts, Radford, Sharp, Seymour, Tickle, Turner, Whiting, Yeaman.
Hull KR: McDonnell, Hall, Galea, Clinton, Withers, Carlile, Watts, Wheeldon, Taylor, Lovegrove, J. Hodgson, Paea, Horne, Murrell, Dobson, D. Hodgson, Mika, Welham, Green.