The front row sees Tom Court and Bryan Young swap positions from last week, with Court starting at loose head prop and Young at tight head. Rory Best does not feature in the squad and is replaced by Nigel Brady as hooker for the side.
In the second row, Italian International Carlo Del Fava will start alongside former RBAI captain Ryan Caldwell. The back row is entirely different from last week with Matt McCullough, Kieron Dawson and Chris Henry all starting, thus relegating Thomas Anderson and Robbie Diack to the bench, David Pollock drops out of the squad.
The backline is transformed with only Paddy Wallace and Timoci Nagusa surviving from the Reds game. Paul Marshall and Paddy Wallace form the half back partnership with Mark McCrea and Nagusa on either wing. Ulster Rugby player and new backs coach Paul Steinmetz, is named alongside Irish International Andrew Trimble in the mid field.
With Williams naming eleven replacements, it looks like he is keen to try out more players ahead of the start of the Magners League next Friday, when Ulster take on Llanelli Scarlets at Ravenhill.
Matt Williams is aware of the challenge Worcester will present and commented: "They are like us, coming to the end of our pre season and gearing up for the start of a big league campaign. It will be another step up, but at the same time, what has been good for us in that we are seeing young players coming through who have shown us they are ready for the next step."
"I have been really encouraged by the players over the last few months in particular for the two pre season games, their commitment and attitude has been exceptional and the Worcester game will be a good test for some players who haven't featured against either Bath or the Reds. We play Scarlets next Friday at Ravenhill and start what we hope will be a successful league campaign, so obviously a win against Worcester would be a great boost for the players."
Worcester have confirmed that Australian International Chris Latham, who signed a two year deal with Worcester last season and transferred this summer from the Queensland Reds, is set to make his Worcester debut at Ravenhill on Wednesday evening.
Australian ace Latham currently stands as the second highest try scorer in Wallaby history and played in every match at RWC 2007, scoring five tries to take his total to 40 tries and 200 points in 78 games for his country.
The 32-year-old started his career with the New South Wales Waratahs before moving to Queensland in 1998. He has been awarded the Australia Super 12 Player of the Year award on four occasions in 2000, 2003, 2004 and 2005.
Worcester Director of Rugby Mike Ruddock said this of the news: "We are delighted to be able to give Chris Latham a first start now he has made a full recovery. He is very keen to get started for the club and we look forward to seeing him in a Warriors shirt for the first time, it will be a special moment for the club."
Tickets for the fixture are still available online at www.ulsterrugby.com, over the counter at Ravenhill and will be available on the gate on Wednesday night.
Ulster Team: B Cunningham; T Nagusa, A Trimble, P Steinmetz, M McCrea; P Wallace, P Marshall; T Court; N Brady, B Young, C Del Fava, R Caldwell, McCullough K Dawson(Capt),C Henry
Replacements: S Philpott, J Fitzpatrick, R Diack, W Faloon, C Willis, T Anderson, I Humphreys, I Whitten, C Cochrane, N O'Connor, R Dewey