Not having Ibaka tonight to deal with Randolph, Marc Gasol, and the Grizzlies' front line would obviously make things much more difficult for the Thunder, both defensively and in controlling the boards. A much heavier burden would fall onto Nenad Krstic (who may still be injured), Nick Collison, Jeff Green, and Kevin Durant to keep the Grizzlies from gashing them again inside the paint.
Also, keep in mind that Cole Aldrich was recently called up, and D.J. White is still sitting on the bench ready to go. White has played sparingly, but when he's gotten minutes he has produced. While neither of these guys are going to slow down Randolph much, they are still 12 extra fouls that can be used to make the man work for his points. It will be up to Scott Brooks to maximize every asset at his disposal to close the hole and give the Thunder a shot to keep their momentum going.