West Brom have taken disciplinary action against midfielder Jason Koumas after he failed to return from his summer break on Tuesday.
Koumas wants a move to Cardiff after spending a season there
The 26-year-old was due to attend a meeting with the club about his future before joining in training.
Koumas spent last season on loan at Cardiff and wants a permanent move.
However, West Brom have told the Wales international he must return to training by Monday or he will face further disciplinary action.
Cardiff are thought to have offered £1.5m for Koumas, with the Baggies wanting that amount up front plus another £500,000 to follow.
Meanwhile, West Brom have completed the signing of Switzerland keeper Pascal Zuberbuhler on a free transfer from Basle.
The 35-year-old, who did not let in a goal in four games at the World Cup, has signed a two-year deal.
"Pascal is a very experienced goalkeeper and with Chris Kirkland leaving, we needed a replacement," said West Brom boss Bryan Robson.
Manchester United are keen to sign West Brom's current first-choice keeper Tomasz Kuszczak.