J.J. Redick has been ruled out action for six to eight weeks due to a fractured bone in his hand.
"It takes out something that's been huge for us offensively," Rivers told reporters.
"J.J.'s movement is often an often in itself. He's one of those guys when he goes out it changes a lot of what we do.
"We're going to have to do it on the run we don't have a lot of time to prepare. We just have to find another way."
Redick is averaging 15.2 points per game this season.