England skipper Sinfield was withdrawn from Friday night's win over the Exiles citing a problem with his thumb.
He said in the immediate aftermath he thought he had dislocated it, but with no news of a diagnosis, the injury-hit Rhinos have called upon him.
With eight first-team players out, coach Brian McDermott has called up England Under-19 captain Jordan Baldwinson, while Ben Jones-Bishop is selected for the first time this year after his recovery from a lung condition.
The Rhinos' other internationals - Zak Hardaker, Joel Moon, Ryan Hall and Jamie Jones-Buchanan - are also included in the 19-man party.
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