The ex-Leeds Rhinos prop has been in terrific form for Rovers this term and earned the club’s man-of-the-match in today’s 28-10 Ladbrokes Challenge Cup defeat to Wigan Warriors.
However, he went down in agony when being tackled in the 71st minute and had to be helped off the field.
Sheens said: “It looks like an ACL which will be the end of his season.
“I’d say overall he’s been our best forward all year so, yes, it is a big loss for us and him, too.
“I think he was being considered for the (England) Knights tour at the end of the year. The coach had rung me.
“In saying that he's got a scan tomorrow so you never know. Im hoping my physio is wrong even though he’s not wrong very often so I’d say we've lost him.”
Rovers also saw second-row James Greenwood go off with a concussion that rules him out of next Sunday’s derby against Hull FC at Magic Weekend and prop Mase Masoe departed with an ankle problem but they hope he will be fit for that.
KR are awaiting to see what will happen with Danny Tickle, too, after the ex-Great Britain second-row was red-carded on the stroke of half-time for a punch on England’s John Bateman.
Sheens, whose battling side were still level 10-10 on the hour, said: “I'm waiting on the charge sheet as he was charged with retaliation so obviously he was defending himself.
“I’m hoping the charge won’t be a savage one, rather than being the aggressor.
“He got punched and he punched back but then there’s been some talk of a heradbutt. I don’t know.
“To get the penalty off it (as Hull KR did) and lose someone to a red card hurts doesn’t it?
“I think the ref’s saying Bateman didn’t punch initially but I’ve not seen the video yet so I’ll comment later when I do.”