Kick-off is 16:00.
Tied with the Buccaneers on 46 points, Ajax find themselves in second place on the log due to goal difference. Ajax coach Foppe De Haan's side has been struck by a number of injuries ahead of the match.
"It does not look good when one sees the list of players who are unavailable for the Wits game but the players coming off the bench have impressed recently," said De Haan on the Ajax website.
"Lebogang Manyama had a good game against Free State Stars at the weekend and he will be in the selection frame come the Wits game, then Willard Katsande has really fitted in well when coming on for George Maluleka or Brent Carelse and he is also in squad for this game."
Ajax will however be boosted by the return of Thembinkosi "Terror" Fanteni.
"A big plus for the away game on Wednesday is the availability of Terror Fanteni. He was ill at the weekend and could not play against Stars but he trained really well since the game and he will make the trip to Johannesburg and the return of Nazeer Allie and Brett Evans is a great boost to our defence. They bring with them experience and stability to the line-up. "
Ajax will be weary of going into the game as favourites, as Wits have turned out a number of convincing victories at home recently and will be difficult to beat.
In the only other afternoon game, Free State Stars will host Amazulu at Goble Park starting at 15:30. Golden Arrows will be at home to Platinum Stars at the Chatsworth Stadium in a 17:00 kickoff.
Bloemfontein Celtic will travel to Santos at the Athlone Stadium in a 19:30 kickoff. Santos with a win will be able to close the gap to three points on Celtic who are one position higher in fifth on 36 points.
SuperSport United will be hoping for a much needed win when they host relegation-threatened Moroka Swallows at Loftus at 19:30.
Mamelodi Sundowns will also be hoping to keep their title ambitions alive as they travel to the Mbombela Stadium to take on bottom of the table Black Aces at 19:30.
In the only 20:00 start, log leaders Pirates host Maritzburg United at the Orlando Stadium.