Midfielder Lee was replaced 12 minutes into the 2-1 league loss, with the teams meeting again at Hampden next Saturday.

The 27-year-old initially tried to continue but was forced to come off.

Manager Craig Levein confirmed the Englishman has "twisted his knee so it doesn't sound great".

He added: "He wasn't supposed to start, but Harry Cochrane got ill. It is never good when he goes back on and comes off again."

Ryan Edwards replaced Lee and defender John Souttar was also withdrawn as a precaution in a much-changed Hearts line-up as both sides rested key men before the final.

Callumn Morrison, Aidan Keena, Ben Garuccio, Demetri Mitchell and Steven Naismith all out with knee injuries, but Levein said he hopes Peter Haring, Arnaud Djoum and Uche Ikpeazu will be fit for the final.