"It's not just the fee, there's the sell-on as well because what you can receive is very important these days," he added.
To illustrate his point, the manager recalled his previous experience developing elite young talent at Carlisle United before they moved on to higher divisions.
"I brought Jarrad Branthwaite through at Carlisle and when he was supposed to go to Manchester United, it was going to generate about £7m for them at the time, so that has to be a consideration," noted Pressley.
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Despite the inevitability of a summer departure, the head coach maintained that the club remains in a strong position as Graham enters the final 12 months of his contract.
"Of course you want to demand as high a fee as possible, but it's beneficial to look beyond that.
Luke has the capabilities to be a centre-back in the English Premier League down the line.
But if he is still here in August, I'd be very happy," stated Pressley.
Meanwhile, Graham expressed his current mindset during a recent media interview while participating in international training duties.
"I was looking forward to getting my feet up. That has changed a little bit (with this call-up).
I will get some time off. I will wind down and enjoy some family time and enjoy my summer.
If something happens then it happens. If it doesn't then it doesn't.
That's the way it works," Graham told the Daily Record.
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The official summer transfer window opens on June 15 and is scheduled to close at 11:00 PM on September 1.
