Porto striker Marc Janko admits several of his teammates plan to leave this summer for bigger clubs.
Fellow striker Hulk has been linked with Chelsea and PSG, while attacking midfielder James Rodriguez is a target for Manchester United.
"Some players want to leave in the summer for a top club. The philosophy of the club is being prepared to, at any time, dealing with possible transfers.
"The club buys cheap and sells dear, and in recent years have done very well with this policy," said Janko.