Louis van Gaal is weighing up using Manchester United defender Tyrell Malacia as a left-sided centre-back at the World Cup and trialled the 23-year-old in the role against Belgium.Manchester United news, exclusives and analysisThe former Feyenoord full-back replaced Nathan Ake at half-time of Sunday’s 1-0 win for the Netherlands in the Nations League, with Virgil van Dijk’s commanding header securing all three points for the hosts in Amsterdam.But rather than lining up in his usual role on the left flank when he entered the pitch, Malacia instead sat alongside Van Dijk and Jurrien Timber in the heart of the defence with Daley Blind remaining at left wing-back.The United new boy gave a decent showing defensively despite his diminutive stature, and Van Gaal says he was keen to trial Malacia in the role after Bruno Martins Indi – Ake’s usual backup – was ruled out of the World Cup through injury.Asked about Malacia’s rather experimental position, Van Gaal told ESPN NL after the game: ‘I put Malacia in the left centre-back role because Martins Indi is not going to make it to the World Cup squad in time due to injury.‘I have to look at other players who can play there and I wanted to see what Malacia could do, so Ake was substituted.’Van Gaal was happy with plenty of aspects of Malacia’s performance in his new role, particularly how he shackled Kevin De Bruyne, but seemed to feel his work on the ball could have been better – with the two even sharing a heated conversation on the touchline after one marauding run forward too many.This time speaking to NOS, Van Gaal said: ‘I put him on the left of the central defence because De Bruyne played a lot on that side.