I dont think its unfair to say hes weaker than some CBs in the air. But playing CB is about your partnership with another or multiple players if you include the keeper coming out for crosses, or playing in a back 3 and having 2 partners
When Rio first came to United I remember people questioning how good he was in the air because he was a lot better on the floor. He had his best times next to Vidic whos strength was being a one man clearance crew from our box. There used to be passages of play where opponents put the ball into our box, Vidic heads it out, the opponents pick it up and keep up the pressure and again it came in and again he would head it out. And again they would pick up the ball and who was there to deal with the cross? Vidic.
So Lisandro not being as strong as some CBs in the air is fine, you just need to make sure he's with someone whos fairly strong in the air. You just dont want 2 CBs who probably the best method to get past them is to cross the ball in and compete in the air. Thats what it would have been like if we signed Timber like some posters wanted. Lisandro is best suited to someone taller and good at clearing the ball out in the air next to him. We have that with Maguire, Evans and Varane. And Argentina have it with Romero
The partners we look at in the future should also be solid in the air to help him out and there will be no issues