On-loan striker Jo has been suspended by Everton after breaching club discipline by returning home to Brazil over Christmas without permission.
The 22-year-old Manchester City frontman has been dropped from the squad to face Carlisle United in the third round of the FA Cup on Saturday by Toffees boss David Moyes and his future at Goodison Park is now in doubt.
"We like Jo but there has to be discipline at football clubs," said Moyes, who signed the South American on a season-long loan from City in July.
"He left over a busy period and left us short of players. We've suspended him from the club.
"It might change but at the moment, that's the situation."
Jo has struggled to adapt to life in the Premier League following his £18million move to Eastlands from CSKA Moscow in July 2008.
The tall striker was prolific in Russian football but managed just three goals in 18 games for the Citizens before being sent out on loan to Everton last season,
Jo rejoined the Toffees in July but has found the net just two times in 24 appearances in all competitions this season.