Published Thursday, 12 January 2012
Both players left the field early in last week's match against Edinburgh at Murrayfield - Humphreys with a hamstring injury and Wannenburg with an ankle injury.
Brian McLaughlin's side for Friday's match at Ravenhill shows just one change with Paddy Wallace to play in the centre, replacing Ian Whitten.
"The whole team has performed well in recent weeks but we have worked on a few things in training this week to ensure that we are in peak condition and are raring to go," said McLaughlin
"The game at Welford Road in round two was very tight and we were really disappointed to come away with nothing.
"To beat Leicester, you have to beat them up front. They play a game based on their set-piece, and that aspect of the game will be crucial for us."
Elsewhere Nigel Brady is preferred to Andi Kyriacou to cover the hooker berth - he will make his 100th appearance for Ulster if he takes to the field during the game.
McLaughlin continued: "Nigel has been a fantastic servant to Ulster Rugby over the years.
"He is an integral member of the squad and has the respect of his team mates and all the staff at Ulster Rugby.
"He is an Ulsterman through and through and he takes great pride in his performance when he takes the field."
The team was further boosted this week with the news that scrum-halves Ruan Pienaar and Paul Marshall have renewed their contracts for another two years.
Ulster: S Terblanche; A Trimble, D Cave, P Wallace, C Gilroy; I Humphreys, R Pienaar (1-8) T Court, R Best, J Afoa, J Muller (Captain), D Tuohy, S Ferris, C Henry, P Wannenburg.
Replacements: N Brady, C Black, A Macklin, L Stevenson, W Faloon, P Marshall, I Whitten, A D'Arcy.