Jim Jefferies tells Hearts not to lose their edge

The manager is also aware of complaints against SPL referees, most recently leaked from Celtic Park, and is cautious that his squad does not compromise their desire to cement their place in the top six at Pittodrie.

Although determined to eradicate "needless" yellow and red cards by drawing up an internal disciplinary code, Jefferies must balance this against making sure his players do not hold back in competition. He has spent this week drawing up a code of conduct which will be presented to Hearts' managing director Campbell Ogilvie for ratification next week. Jefferies stressed the need for unquenchable spirit from his squad blended with a bout of common sense on the field.

"That will be one of the things that go up on the (disciplinary] sheet. I'll be making them aware we want the competitive edge," he said. "Competing is not talking back to a referee when he's made a decision. We had one incident recently where Christian (Nade] kicked the ball away and was booked and ended up being sent off. The players need to learn to be professional, that's the key.

"It hurts the club in ways if someone is sent off but it also hurts the player as well because it could cost him his place in the team. He could find himself losing more than one appearance through his own stupidity. Aberdeen will be smarting from two defeats tomorrow. Their confidence will be a bit fragile so if we can go and perform well and maybe get in front, then we can go and take advantage. I think they will look at beating us 3-0 the last time and highlight positives rather than negatives. I'm expecting them to show a reaction to their last two defeats. If we can show the same spirit and application as we have in the last couple of games, we can make sure they don't have it as easy as last time."

Hearts are without Marian Kello due to a fractured wrist so Janos Balogh will start in goal. Spanish winger Suso remains doubtful with a thigh complaint and midfielder Ian Black is definitely out along with Nade, who is unavailable pending the results of a disciplinary inquiry.

Ismael Bouzid resumed training yesterday and Gary Glen and Michael Stewart are available again after injury and suspension.