Justin Fitzpatrick will start against the Scots at loosehead prop, replacing Bryan Young who drops to the bench. In the second row, Ravenhill favourite Justin Harrison is named alongside Carlo Del Fava in what could be Harrison's last start for Ulster before his move to Bath.
The back row is all change with Neil Best replacing Kieron Dawson and Roger Wilson named at number 8 with Stephen Ferris unavailable due to an injury picked up during Wednesday's win over Munster.
Full-back Bryn Cunningham drops out of the squad after fracturing his cheekbone on Wednesday evening, with Mark Bartholomeusz set to don the number 15 jersey and fit-again Scottish international Simon Danielli coming onto the left wing.
Commenting on Cunningham's injury, Williams said: "I'm really disappointed for Bryn. He didn't realise the damage or complain about the pain until well after the game. It just came on him when he cooled down and proved to be a fracture and we are all disappointed for him."
With Isaac Boss again starting at scrum half, Kieran Campbell has been named on the replacements bench ahead of what could be his last run-out for the province before his switch to Connacht.
"Glasgow are a side who have improved enormously throughout the last season. They play an open and attractive style of rugby and I know some of the players well so I am looking forward to this fixture," Williams admitted.
"With the week we have had, the game against Glasgow is a huge challenge. Training has gone well this week, clearly the fixtures and scheduling isn't perfect but I have had no complaints from the players - they know they just have to get on with it.
"The boys showed real pride on Wednesday night in their defence and Saturday will be no different. It will be another hard 80 minutes and mentally it is all about the heart and playing for the shirt."
Tickets are still available for the Glasgow game at the Ravenhill counter, over the telephone on 02890493222 (Option 2) and they will also be available on the gate from 1.30pm on Saturday.
ULSTER (v Glasgow Warriors): Mark Bartholomeusz; Tommy Bowe, Andrew Trimble, Rob Dewey, Simon Danielli; Paddy Wallace, Isaac Boss; Justin Fitzpatrick, Rory Best (capt), Tom Court, Carlo Del Fava, Justin Harrison, Matt McCullough, Neil Best, Roger Wilson.
Replacements: Nigel Brady, Bryan Young, Ryan Caldwell, Kieron Dawson, Kieran Campbell, Niall O'Connor, Mark McCrea.