Chelsea are unhappy with the limited playing time Danilo Pantic and Nathan have been getting at Vitesse this season.
Chelsea assistant first-team coach Eddie Newton has warned Vitesse they are in danger of missing out on signing the Premier League side's best youngsters on loan in future if they do not get regular playing time.
The Eredivisie side signed Dominic Solanke, Lewis Baker, Isaiah Brown, Danilo Pantic and Nathan on loan at the start of the season, but the latter two in particular have been struggling to secure regular first-team football.
Baker and Brown have both spent plenty of time on the bench as well, with only Solanke a regular starter if fit, and Newton has stressed it is vital for the club's loanees to get regular game time.
"It's all about the players' development for us," Newton - who was loan-player technical coach at the club until December - told Voetbal International when asked about the situation of Chelsea's youngsters at Vitesse.
"There are things that are important to us. Firstly, the player's development on and off the pitch. Do they improve as a player, get more clever, more independent and things like that?
"But the second is at least as important and that is whether they are getting regular playing time.
"A player's development is in danger if they do not play often enough. We will have to look at other clubs if that is the case."comments