Questions on the future of Manchester United striker Rooney, who was this week the subject of a bid from Chelsea, were not permitted as Mourinho spoke on the Blues' arrival in Malaysia.
Rooney was reported to be "angry and confused" after United boss David Moyes suggested he was second choice behind Robin van Persie, whether intentionally or not.
When asked about Brazil 2014, Mourinho did not refer to Rooney - his sole transfer target - but his message was clear.
"Any player that wants to go to the World Cup, if they are a second choice at their club, then they're in trouble, they're in trouble," Mourinho said.
"This is a crucial year for that and many national team coaches are worried because they want players to play regularly for their teams."