Martinez made his first appearance for the Reds on Sunday, during the 1-1 friendly draw with Rayo Vallecano.
The Argentina international impressed while playing 61 minutes against the Spanish side.
He lined up in central defence, alongside Raphael Varane, but ESPN journalist Rob Dawson believes he could be deployed further up the field if needed – as he was at times for his former club Ajax, under Erik ten Hag.
“In terms of the balance of the squad, I’m surprised we’re not hearing more about Martinez playing midfield,” Dawson said. “He did that at Ajax occasionally.