Manager Russell Slade has said Cardiff are looking at whether Juan Cala broke club discipline rules on social media.
Aston Villa boss Paul Lambert has defended his decision to send striker Darren Bent out on loan to Brighton.
Defensive midfielder Kevin Pannewitz has signed a two-year contract at Wolfsburg from German third-division side Hansa Rostock.
The 21-year-old is regarded highly by Wolfsburg manager Felix Magath, although his new coach has warned him he must work hard and maintain his focus if he is to maximise his potential.
"Kevin has the potential to be a Bundesliga player, but unfortunately he has not dealt with his talent professionally in recent years," said Magath.
"Now he will get a second chance with us and I hope that he takes advantage of his new surroundings."
Pannewitz has spent his whole career in the north of Germany, making 32 second division and 35 third division appearances for Rostock.
He was offered a trial by Magath at the end of the season and appeared in several friendly matches, managing to convince the much-travelled manager to take a gamble on him.