The Tynecastle side fell 2-1 at Celtic Park but manager Craig Levein was more concerned about Lee’s fate after he was forced off off just 12 minutes into the game. The player had earlier tried to run off the knock but was eventually replaced by Ryan Edwards.
To make it more frustrating, Lee had not been meant to start. Harry Cochrane was supposed to be in the team but fell ill overnight.
“So it’s just sod’s law,” said Levein. “We will just have to see because I would be guessing if I said anything else. But the fact he’s had to come back off again is never a positive sign.
“We have a few on the sidelines who I’m hoping could come back, that’s Uche Ikpeazu, Peter Haring and Arnaud Djoum. John Souttar’s groin was a bit sore at half time and Michael Smith’s calves were tight.”
Hearts started the game with three teenagers – Andy Irving, Connor Smith and Aaron Hickey, who is just 16 – as they fell to their sixth league defeat in their last seven outings.
“I wouldn’t say it was low-key but there will be a lot more going on next week,” said Levein. “We have made changes with the sole purpose of trying to get everyone fit and available.
“I thought the kids who came in did really well. I was pleased with all three of them, I thought they did really well.”