Spence worry for Raith
Raith striker Greig Spence is a major doubt for his side's clash with Hearts at Stark's Park as he is still feeling the effects of a thigh strain.
Liam Fox is expected to face the Tynecastle men after missing Saturday's goalless draw with Dundee due to a leg knock.
Raith boss Grant Murray is telling his players to make the most of the tie, saying: "Having Hearts at home in a cup-tie is a big game in any player's career.
"You don't get many games like this in your career and I want our players to enjoy it and make it memorable by putting on a terrific display."
Meanwhile, Hearts defender Danny Wilson has been handed a one-match ban following an alleged tunnel bust-up with Aberdeen boss Derek McInnes.
The incident followed a drama-filled encounter at Tynecastle that saw the 10-man Jambos snatch a stunning victory when 17-year-old substitute Jordan McGhee grabbed a late winner.
Left-back Kevin McHattie was dismissed for bringing down Dons striker Calvin Zola, while Gorgie assistant boss Billy Brown and McInnes were both sent to the stands following a dug-out confrontation in the seconds after McGhee's decisive strike.
Now the Scottish Football Association has confirmed Wilson was shown a red card after the 90 minutes following an argument with the Pittodrie manager in the Tynecastle tunnel and will miss next Saturday's trip to Inverness.
A spokeswoman told Press Association Sport: "Danny Wilson was shown a red card for foul and abusive language after the final whistle.
"He will be suspended for one Scottish Premiership match."
Speaking before the SFA released their actions, Locke admitted he had not seen the disagreement: "I'm still waiting to hear the report of that one because I'm very much in the dark.
"I didn't know anything had happened until somebody brought it to my attention, so I don't want to comment on it because I don't know much about it.
"We will need to get clarification on it because I need to know who I will have available for Saturday."
The SFA also confirmed that the incident involving McInnes and Brown was not a fast-tracked issue, so would not be dealt with by compliance officer Vincent Lunny immediately.
The spokeswoman added: "If the incident is mentioned in referee's report, Vincent Lunny will write to the individuals involved and ask them to explain their actions."
However, Hearts do hope to overturn defender Kevin McHattie's weekend red card after a generous supporter offered to cover the B#500 cost the administration-hit club will have to fork out for an appeal.
Locke is convinced his man won the ball in the penalty-box incident which led to Niall McGinn's second-half spot-kick equaliser.
And with Hearts currently banned from signing new players as a result of the punishments handed to them for breaking insolvency rules, he is loath to lose any more members of his squad and hailed the "special offer" the club had received.
Locke will be able to pick McHattie for the League Cup clash with Raith, regardless of his appeal, as the one-match ban he is due to serve will only apply to Scottish Premiership fixtures.