Jamie Walker faces up to three months on the sidelines after picking up an injury in Friday night’s Betfred Cup win over Motherwell.
The midfielder was forced off during the first-half at Fir Park and scans have since shown that he’s fractured a fibula in his leg.
Walker, who returned to the club during the summer, now faces a period of rest and rehabilitation as he targets a return to action around December.
Speaking to the heartsfc.co.uk, manager Craig Levein said: “I’m obviously very disappointed for Jamie, especially when it looked like he was beginning to hit the form that we know he’s capable of.
“We have a very good medical team here at the club and I’m sure they and Jamie will work hard to get him back and in peak condition in three months time.
“We’ve now lost three key players in our last three games; John Souttar was taken off against Aberdeen, Steven Naismith against Ross County and Jamie on Friday night so I only hope that our luck will change soon on the injury front.”