Despite trailing Barcelona in the LaLiga title race, Mijatovic says Real Madrid should keep their powder dry.
He said on El Larguero: "Big teams go into the winter transfer market thinking more about the future than the present, because January isn't a good month to sign a player.
"Firstly, because you're not going to find someone who will come in and start playing from minute one."
Mijatovic, who knows the Real board well, insisted that the January window offers few real opportunities.
"If someone comes in, it has to be a young player with a lot of potential, or if you have an injured player, you sign someone who isn't playing for their team. Because nobody is going to let you have a key player on the transfer market. So, the winter transfer window isn't very useful," he pointed out.