The line opened with the Cardinals as a 2.5-point favorite this week, though has shrunk to around 1-1.5 for most online betting sites, according to Oddsshark. The over/under opened the week at 38.5, but has expanded to 39-39.5.
The total has gone under in four of the Cardinals' last six games, and four of their last five on the road. They are also 10-1 in their last 11 meetings with St. Louis, while the Rams are 0-5 in their last five against Arizona at home.
Over at Walter Football, they note that 70 percent of all Las Vegas bets have been placed in favor of the Cardinals thus far.
Kickoff is set for 5:20 p.m. PT with coverage on the NFL Network.