He wants his future to be sorted this week, prompting a move away from the club, with interest coming from Italy.
Rafa Benitez has signed right-back Jesus Gamez from Valencia and he also took 20-year-old Jamie Sterry to County Kildare.
Janmaat, however, will get a chance in the club’s pre-season campaign, which kicks off with a game against Dublin side Bohemian at Dalymount Park on Saturday.