Real Madrid have confirmed goalkeeper Thibaut Courtois is set for a spell on the sidelines after suffering an injury to the left iliac muscle.The Belgium international has joined an increasingly long list of players in the treament room at the Santiago Bernabeu, with the likes of Marcos Llorente, Marco Asensio, Gareth Bale, Toni Kroos and Mariano Diaz also out of action at present.It’s believed that Courtois’ injury will keep him out for around a fortnight, with Keylor Navas set to deputise for the Galacticos in his absence. Article continues below Editors’ Picks ‘There is no creativity’ – Can Solskjaer get Man Utd scoring freely again? ‘Everyone legged it on to the pitch!’ – How Foden went from Man City superfan to future superstar Emery out of jail – for now – as brilliant Pepe papers over Arsenal’s cracks What is Manchester United’s ownership situation and how would Kevin Glazer’s sale of shares affect the club? A Real Madrid statement read: “Following tests carried out on our player Thibaut Courtois today by the Real Madrid Medical Services, he has been diagnosed with a grade I injury in the left iliac muscle. His recovery will be monitored.”Courtois completed the full 90 minutes in Real’s previous match, a 2-0 loss at home to Real Sociedad and he is also believed to have trained for the majority of this week in the build-up to his side’s Copa del Rey tie against Leganes on Wednesday.Navas, who had been Real’s number one goalkeeper up until Courtois’ summer arrival, was expected to start their latest cup clash regardless, but the former Chelsea stopper is now likely to miss both legs of the tie, as well as the club’s upcoming league matches against Real Betis and Sevilla.Santiago Solari’s side are in desperate need of some positive results after their defeat to Sociedad left them languishing in fifth place in La Liga and 10 points adrift of leaders Barcelona.The 13-time Champions League winners have endured an extremely underwhelming season to date, having only won half of their 18 league matches so far and losing six.Former Spain boss Julen Lopetegui was in charge at the beginning of the season, only to be sacked in late October after a poor start to the season.