Aberdeen boss Jimmy Calderwood says Zander Diamond has to become more "streetwise" if he wants to reach the highest level in the game.Diamond looks likely to miss this weekend's SPL match with St Mirren having been injured in challenges against Celtic striker Jan Vennegoor of Hesselink on Tuesday night.

The Scotland under-21 international played his part during Aberdeen's shock Scottish Cup triumph at Parkhead but had to be replaced after 64 minutes.

Diamond was caught by an elbow in the face on two separate occasions by Vennegoor of Hesselink and has been left with blurred vision in an eye.

Calderwood does not think the Dutchman was malicious in his attempts to win ball though and maintains Diamond will just have to learn the right times to be brave.

When asked for his opinion on the incidents with Vennegoor of Hesselink, Calderwood said:

"I only saw the second one and I don't think there was too much in it to be honest.

"People tell me the first one was worse, but on the second occasion Jan was already up there and Zander just has to learn to be a little bit more streetwise.

"He is so honest and goes for every ball.

"But if the striker is up before you, then you are not going to win it.

"So you just need to sit off and win the second ball."

Calderwood added:

"You have to learn that side of the game quick because it can be a both hard and cruel.

"I think the lad has all the qualities to go very high, but the higher you get the harder it is.

"It can get a bit nasty sometimes."

Calderwood outlined that although Diamond was up against a Dutch international at Parkhead during the week, it can be far tougher when dealing with top players from other nations.

He said: "The Dutch aren't as physical as other countries and if you are playing against Italians or Argentineans or Uruguayans then you have to protect yourself.

The Aberdeen boss stressed the importance of knowing how to deal with the rough and tumble of football saying: "If you see somebody coming and there is going to be a tackle that will put you in hospital, then you need to know what to do."

If Diamond does miss out then it is probable he will be replaced by Lee Mair, just as happened at Parkhead.

Calderwood praised Mair for coping well when pitched into battle against Celtic and is pleased to finally have options at his disposal, having been forced to deal with a lengthy injury-list at Pittodrie this season.

He said:

"It is difficult to come on a substitute, especially in those circumstances and Lee did great.

"At least we have a little bit of cover at this moment in time, because there have been other times when we've had kids on the bench."

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