Horne has been an ever-present for Hull this season

Stand-off Horne has fractured his sinus bone and cracked an eye socket while prop King has undergone exploratory surgery on torn knee ligaments.

"Richard has no chance for the Tri-Nations," said Hull coach John Kear. "We've been told he's out for a minimum of eight weeks and a maximum of 12.

"Paul King has had exploratory surgery and is out for the season."

The loss of Horne and King is another body blow to Hull's play-off hopes, having already lost skipper Jason Smith with a cracked shoulder bone.

They play their final match of the regular season against Widnes at the KC Stadium on Saturday.