It's almost as if managers have forgotten to give their defenders the pre-season talk about avoiding reckless challenges, because, after all, it is only a friendly game.We've seen Lisandro Martinez go flying into poor challenges twice now. The first time was at Bukayo Saka's expense, who was lucky to avoid injury as Arsenal were defeated 2-0 by Manchester United. The second time then came against Real Madrid, as Jude Bellingham was recklessly taken out, sparking the midfielder's fume.Now, it seems as though Barcelona defender Ronald Araujo has caught the recklessness bug, leaving no prisoners against Arsenal, as he wiped out Gabriel Jesus in a needless challenge.The forward fortunately managed to avoid injury, but there's no doubt that he was left unpleased, with nothing really riding on the game to warrant such aggression from the Barca man.