England head coach Eddie Jones has revealed that he has taken note of 'three of four players' not playing up to standard for their clubs.
The warning from the head coach comes less than a month since England clinched the Grand Slam.
Jones is monitoring several players ahead of England's tour to Australia in June and admits that some players need to pick up their form in order to make the tour.
"Personally I've been disappointed in three or four players who have gone back [to their clubs] and played quite poorly," Jones told the BBC.
"Those players have put their tour place to Australia in jeopardy.
"Some might have little injuries, and some of them have agents or the media in their ear telling them how good they are. They have just got too far ahead of themselves.
"We should be happy, but we have also got to be quite aware that we have got to keep improving. Some of the players have been told directly, some of them have been told through other sources.
"But they will get the message. We'll see on the rugby field – 80 percent [are playing well], 20 percent are not, so there could be 20 percent change in the tour squad."
Jones also discussed the possibility of adding Leinster and future Worcester centre Ben Te'o to his England squad, describing the South Sydney Rabbitoh star as "definitely in contention".
"He has to be eligible, and that will be decided between the RFU and the clubs," Jones added.
"If he is eligible then he is definitely in contention because he's a good player. He can carry through the line, he can pass, he's a good defender.
"He's made a decision to play for England. [Discussions over his eligibility] are moving in the right direction. I haven't met him but I've had a few phone and text conversations with him."