The match will be played at the General Seyni Kountche Stadium, starting at 3.30pm local time in Niger (4.30pm in South Africa).
Earlier coach Pitso Mosimane said he had brought 23 players to Niger so if Mphela was unable to play, it would be an opportunity to give another player a chance.
"I did the same in Cairo with Steven Pienaar, so we will wait, but I am hopeful he will make it."
South Africa arrived at the stadium to the welcome of hundreds of Nigerien fans who wanted to watch the training session.
The coach signalled a warning that people should not expect beautiful football as the main target would be to earn the three points.
"We have to play for a win against Niger so we don't have to play for a result against Sierra Leone next month.
"The mentality I have instilled in the players is about winning the match, and a draw will be the worst result for us.
"We are not in Niger to play beautiful fancy football and show South Africans how we can play - the South Africans know that we can play fancy football, now what they want is for the team to qualify and we have to do everything in our power to qualify.
"The formula has been to get three points at home and, at worst, get a draw away - I must say so far so good, but the ideal way to do things would be to win every match," Mosimane said.
Bafana Bafana will be captained by midfielder Siphiwe Tshabalala, who will also be making history when he runs onto the field against Niger.
With 61 caps for South Africa, Tshabalala will become the most-capped Kaizer Chiefs player with 53 caps as an Amakhosi player while the other eight he earned while playing for Free State Stars.
He will surpass the record of 52 caps held by former Bafana Bafana and Chiefs captain and defender Neil Tovey. Tshabalala is also the highest-capped player in the current squad.
"As a young player, I always looked up to the likes of Tovey, Mark Fish, Lucas Radebe, Shaun Bartlett, Eric Tinkler, Doctor Khumalo and many more, and now to better the record set by a legend like Neil is just amazing," said Tshabalala.
"It's a great honour to have reached this milestone and I intend to lead from the front to help my country to victory."
Tshabalala was not worried by Niger's record of not having lost at home, and believed they could change that despite missing several key players due to injuries.
"We are missing some players, but as a national team we have players in our midst who need to raise their hands and fight for their country.
"It's going to be tough because they [Niger] are also desperate for a win.
"We missed out on qualifying for the 2010 AFCON, so it's very important for us to make it to Equatorial Guinea and Gabon. The object is three points, but we will take a draw if it comes," added the Bafana Bafana captain.