Build up a relationship with the guy, and most important, his agent.
Tell him : look, we believed in you and allowed you to be where you are now
then go like : here , we dont have alot, but have this 5 mil wage as a sign of our trust.
in 3 years, improve it to 6-7mil if he's worth it relative to the team.
Make him have many reasons to feel we went 100% for him, and he might just decide to stay here