Lo Celso has been outstanding for Betis this season, but will not face Legia with the derby against Sevilla this weekend.
Haro said: "Well, it's a technical decision. When I say technical, I mean the coach, the medical team, the sports management.
"I also understand that it has to do with a player who is being fundamental and we have to be careful because he has a lot of work to do with matches.
"We expected him to perform at a similar level to what he had here, but he is performing at least two games above, with more maturity, but he is a player who seems to be made for Betis and he has landed on his feet. I am very happy with the player's performance, the player is happy here in Seville and very happy."
