His natural position is at centre back and United has plenty of left backs at the club already, so I do feel like Ten Hag is planning to play him at the heart of the defence. I think he'll find it really hard to cope, especially at the beginning.
Manchester is willing to spend around 46 million for Lisandro Martínez. For a defender to spend that amount of money is really too much. But Manchester United coach Ten Hag still wants Lisandro Martínez in the team. Ten Hag is well aware of Manchester United's weaknesses. Last season we saw United's poor defending. And so the United management is spending so much money to strengthen their defense.