Albert Kelly is likely to miss Hull KR's Challenge Cup final against Leeds Rhinos on 29 August with a knee injury, says head coach Chris Chester.
Playmaker Kelly featured in three of Rovers' four cup games this season.
The 23-year-old, who scored in two cup ties and has crossed for 15 Super League tries this term, was left out of Saturday's Qualifiers win over Leigh because of a Grade Two ligament tear.
"If I was a betting man I'd say he wouldn't make the final," Chester said.
Rovers are already without fellow half-back Terry Campese, who is out for the season with knee problems.
Opponents Leeds lost hooker Paul Aiton to a broken arm in victory against Warrington on Friday night.