"We have to do something to spark our passing game,” Fox said. "Jimmy is a guy we think highly of. We’ll give him an opportunity. We thought he made the most of his opportunities on Sunday."
Clausen spelled Moore during the fourth quarter of Sunday's 20-7 loss to the Tampa Bay Buccaneers.
Moore, who started despite suffering a concussion in Week 1, completed just 6 of 16 passes for 125 yards and one touchdown with one interception against the Bucs.
Clausen completed that many passes on his first drive, but it ended with Jonathan Stewart stuffed shy of the goal line with Carolina trailing 20-7.
Clausen was later picked off by Aqib Talib and finished 7 of 13 for 59 yards.
Moore has had two miserable weeks. He threw three end zone interceptions and lost a fumble before leaving with a concussion in a season-opening loss to the New York Giants. He has a passer rating of 41.8.
Clausen was taken by the Panthers with the 48th overall pick after a surprising slide in the 2010 NFL Draft.