Oddsshark has San Francisco as 5 point favorites, which hasn't moved much from last week's opening line when the Niners topped the Atlanta Falcons and the Ravens upset the New England Patriots to reach the big game. This line is consistent with other online betting websites -- 5Dimes favors the Niners by 3.5, Bovada has them at -4.5, and Just Bet and Bet Online both have the line set at -3.5 in San Francisco's favor.
This isn't the first time the Ravens faced heavy odds in the playoffs -- they were nearly double-digit underdogs against both the Broncos and Patriots. The Niners are probably the best team they've faced yet this season, but if you're a betting man, this is a tempting bet to at least have them cover the spread.
San Francisco and Baltimore kickoff at 6:30 p.m. ET next Sunday on CBS.