Saints boss Ronald Koeman has revealed the Senegal forward had to take a detour via Ghana on his journey back to England after scoring in his national side's 2-0 victory in Botswana on Wednesday night.
Mane is expected back at Southampton on Friday from African Nations Cup duty, Koeman explained.
The 22-year-old transfer-window capture had to make his stop-off in Ghana to fulfil work permit requirements.
Mane is still awaiting his Saints debut after joining the club from Red Bull Salzburg in an £11.8million deal.
"I hope he can still be involved," said Koeman, ahead of Saturday's St Mary's Stadium meeting with Newcastle.
"He played on Wednesday night and then he had to travel to Ghana to get his passport stamp before coming to England.
"So hopefully he'll be back on Friday."
Former Dutch defender Koeman said Mane could take a seat on the bench if he makes it back in time for the Newcastle clash.
The new Saints boss will most likely start Dusan Tadic and Shane Long up front, given other injuries in his forward line.
"It will be a late decision to see if he is available," said Koeman.
"Maybe he can still play, but we have to wait until Friday.
"He won't be able to train, but he's experienced enough to play if needed and he would probably go on the bench.
"We have injuries to Lloyd Isgrove and Sam Gallagher, so we don't have too many forwards available at the moment."
Koeman has backed Mane to make a big impression at Saints, now the south coast club's squad is settled after the transfer window closure.
"Sadio brings a different quality to the team: a player who is very fast with a good threat of goals," he said.
"We don't have a lot of forward players and with his quality he brings a little bit more to us to find space.
"He's very fast and it's difficult for players to mark that kind of player
He needs time to adapt of course, but he has the quality
"The Premier League is a higher level than he was used to in the league with Red Bull, but he has played in the Champions League so he has already been exposed to a high quality of opponent."
Koeman also revealed loan signing Toby Alderweireld has no recall clause on his season-long deal to join Saints from Atletico Madrid.
The Belgium defender has replaced Liverpool capture Dejan Lovren, with Koeman holding high expectations for his new addition.
"We knew other clubs were interested in Toby, I'm very happy that he finally chose Southampton," said Koeman.
"He knows me I know him and, okay, the adaptation is a little bit easier for Toby.
"First of all it's a quality player and we are happy.
"He shows his qualities from the highest level possible, he will bring a lot of quality in the team and competition for the defenders."
Source : PA
Source: PA