Souttar felt tightness in his hamstring, while Lafferty had to be replaced in the 84th minute after crumpling in pain under a challenge as the Edinburgh side suffered their first defeat at Tynecastle in a year.
The key duo were due to be assessed today, but manager Craig Levein admits he isn’t overly confident about having them available for the visit of Hibs this week.
“John and Kyle are both a concern for Wednesday,” he told the Evening News. “John had a tight hamstring towards the end but I couldn’t take him off because we had used all our substitutes.
“Kyle got fouled, which was another free kick we didn’t get. After he got tripped, he twisted and felt something in his Achilles. I’m a little bit concerned about that. It might just be a kick and he might be okay, but I don’t know yet.”
Levein was pleased to have on-loan duo Joaquim Adao and Demetri Mitchell back in the starting XI yesterday following one-month and two-month lay-offs respectively. “The two of them did well for their first games back, but they’re both tired,” said the manager. “In an ideal world, Demi would have come off at some point.”