Callum Davidson fears St Johnstone defender Scott Tanser's Hampden hopes have been snuffed out by injury.
The left-back hurt his ankle during extra-time of Sunday's Scottish Cup thriller with Rangers.
He had to be replaced before Zander Clark's one-man heroics helped fire the Betfred Cup winners into the semi-finals as they edged out Steven Gerrard's team on penalties.
Davidson's Perth outfit will now face St Mirren a week on Sunday as they bid to reach their second Hampden showpiece of the campaign on May 22.
But 26-year-old Tanser – an unused substitute when Saints lifted the League Cup against Livingston back in February – looks set for further disappointment after his injury blow.
"The likelihood is that Scott will be out for the rest of the season," confirmed Davidson.
"He got a bad injury the other night. He rolled his right ankle then rolled his left, so poor lad.
"Unless we get some good news in the next couple of days from the scans we're waiting on it looks like he'll be out for the rest of the season."