The No. 1-ranked team is a touchdown underdog to start the week.

No. 2 Alabama has been installed as a 6.5-point favorite over top-ranked LSU in an SEC showdown potentially featuring two Heisman Trophy frontrunners at quarterback on Saturday in Tuscaloosa, Alabama.

Crimson Tide quarterback Tua Tagovailoa has been out since suffering a high-ankle sprain in a win over Tennessee on Oct. 19. He underwent surgery the next day and missed Alabama's win over Arkansas, before returning to practice in a limited capacity last week.

Crimson Tide coach Nick Saban has maintained that Tagovailoa's availability against LSU will be a "game-time decision."

Multiple U.S. sportsbooks initially made Alabama a 7-point favorite, but the consensus line as of Sunday afternoon was Crimson Tide -6.5. Oddmakers told ESPN that the current line reflects Tagovailoa playing. If Tagovailoa is ruled out, and redshirt Mac Jones is inserted as the starter, oddsmakers say the line would shift dramatically, likely leaving the Tide as a small favorite or potentially even turning LSU into the favorite.

Alabama has been favored in 62 consecutive games and 133 of its last 134 contests. The Crimson Tide were 1-point underdogs at Georgia in 2015.

Tigers quarterback Joe Burrow is the favorite to win the Heisman Trophy at 6-5 odds at the SuperBook at Westgate Las Vegas. Tagovailoa is 3-1.

Since 1978, there have been six games where the No. 1 team in the AP Poll was at least a touchdown underdog. Most recently, top-ranked Clemson was a 6.5-point underdog to No. 2 Alabama in the 2015 College Football Playoff Championship Game.