Erik ten Hag has said he will be Cristiano Ronaldo’s friend or teacher depending on what is required to manage him productively for the team, but the Manchester United manager has concerns about the 37-year-old’s fitness. “I will be his friend and sometimes I will be his teacher. It depends on the situation,” said Ten Hag of the striker who failed to secure his exit from the club in the summer transfer window. However the manager is troubled by Ronaldo missing most of pre-season because of a family matter. “As we all know he didn’t have the pre-season and you cannot miss the pre-season,” said Ten Hag. “It is a base and especially in the game we play, the way of play. We play another type compared to last year. It depends on the demands, cooperation and certain positioning [of players], in and out of position, and the other thing is fitness.” Ten Hag is pleased with Lisandro Martínez, one of his summer signings, but wants the Argentinian to improve. “I wanted him [he is] a ball-playing defender but also you see his defending capabilities,” he said. “His toughness, his positioning, his anticipation and togetherness. I know what he is able to do. This is a base – he is doing well but he has to do much better.” Martínez was bought from Ajax along with Antony, with Tyrell Malacia also joining from a Dutch club, Feyenoord. The manager was reminded of the uneven record of signings from the Netherlands. “First, the players who we signed are internationals for their countries,” said Ten Hag. “They performed really well in the Champions League and thirdly looking at their individual skills they are capable of playing high-intensity football.”