Obafemi Martins could miss the start of the 2008/09 campaign following the death of his mother.
The Newcastle striker has flown home to Nigeria to be with his family, with no indication as to when he will return.
Martins' mother reportedly died of shock after trying to escape when a petrol tanker caught fire near her Lagos apartment.
"Oba was closer to our mother than anyone else in the family," said his brother Biola.
"He's still in shock and disbelief and feels terribly down. Oba always consulted her first in any decision to do with his career.
"Our mother stood by him when everyone else condemned his decision to dump school in pursuit of an unpredictable future in football."
Martins will now miss the Magpies' friendly date with Doncaster on Saturday, while it is doubtful that he will join his team-mates at the club's training camp in Majorca next week.
As a result, he is likely to be a fitness doubt heading into the new season and Kevin Keegan may be forced to utilise his other attacking options during the first few weeks of the campaign.
A spokesman for the North East club confirmed that Martins had been granted permission to leave the fold, saying: "Oba has flown back to Nigeria on compassionate grounds to be with his family at what is a very sad time for them.
"Everyone at the club extends their greatest sympathies to Oba and his relatives."