Coach Ken Whisenhunt said Monday that X-rays showed a fractured fibula. Davis started the game in place of Clark Haggans, who has missed three of the last four games with a groin injury.
Whisenhunt said he expects Haggans back this week and, with rookie O'Brien Schofield now the backup, does not anticipate adding another player at that position.
Davis, a sixth-round draft pick out of Illinois in 2009, had started the three games that Haggans was injured.
Defensive end Calais Campbell was in a walking boot Monday after spraining his left ankle.