He was forced off after just five minutes of the Edinburgh club’s 2-1 defeat in the first leg of the Europa League play-off in Switzerland. The damage will be assessed once the team arrive back in Scotland on Friday.
“Craig got a tweak on his hamstring when he stretched for the ball,” said manager Robbie Neilson after the match in St Gallen. “We’ll fly back tomorrow and get it assessed then and see where we are. It could be five days, it could be five weeks. He’s walking.”
Lawrence Shankland’s first-half penalty put Hearts 1-0 ahead but Zurich scored twice in quick succession soon after through Adrian Guerrero and midfielder Blerim Dzemaili to earn a slender advantage for the return leg.
"I was delighted with the performance of the players, I thought they were absolutely outstanding tonight,” added Neilson. “We’ve come here against the Swiss champions, a top team, international players, and we’ve performed very well.
“We’ve got the goal, playing exceptionally well and then two sloppy goals in quick succession but we then steadied the ship and get through the game. The game now goes back to Tynecastle and the main objective coming here was to make sure we give ourselves a chance. We’ve done that.
“It’s difficult to come to these places and play against top teams. We’ll give it everything at Tyencastle and try to get through.
“I just wanted the game to stop after we scored, that would have been great. You know they’re going to come into the game.
“I was delighted for Lawrence to get off the mark in Europe. We had that wee period where we started to sit a wee bit and managed to get half-time at 2-1. We had to change it a wee bit in the second half because we were starting to sit deeper and deeper.
“I thought the pitch as very good. It’s a different ball, different surface, different team, it’s a big learning curve for all the players.
“We’ve only got a couple of guys who have played at this level and every time they do it they get more experience. Next week, with the atmosphere, we’ll give ourselves a right good chance,
“I’m pretty sure it will be raucous at Tynecastle. The fans today were outstanding. We’ll have another 18,000 of them next Thursday and I think it will be a brilliant night.”
Franco Foda, the Zurich coach, lamented his team’s failure to kill the tie by scoring more. “We played a good match, we matched to get a deserved win, but the only thing that I’m not happy about is that we had a lot of chances in the second half and didn’t make them count.
“I don’t worry about that coming back to haunt us. I think we’ll have a lot of chances in Scotland as well but we’ll have to be better in using those chances and be cold-blooded in front of goal. Of course it would have been nicer if we had score one or two more goals.”