The quarterback position has been a revolving door for the Vikings this season.
Christian Ponder started the first three games, but was then replaced by Matt Cassel. Cassel started two games before the team signed Josh Freeman and inserted him into the starting lineup. Freeman's time as a starter lasted just one week, and then Ponder re-claimed the starting job and has started the last six games.
But now Ponder is likely to miss Sunday's game because of a concussion, meaning Cassel is back under center.
As the Ravens have gone through the week of preparation with some uncertainty about who they will see from Minnesota, the message from defenders has been to focus on the NFL's leading rusher rather than worry about the quarterback.
"We expect the offense to be built around [running back] Adrian Peterson, and then they've got the complements off of that with the play-action passing and the different things they do," Head Coach John Harbaugh said. "So we'll prepare for the offense and then plug the quarterback in as we go."
The Vikings have not officially ruled Ponder out, but he has to clear the NFL's concussion protocol before returning to action. Freeman only appears as an emergency option after sliding down the depth chart since signing in October.
All three quarterbacks have struggled for Minnesota this year, as their passing offense currently ranks 25th (210.6 yards per game) in the NFL.
Cassel has the team's highest quarterback rating at 84.6, completing 63.6 percent of his passes for five touchdowns and four interceptions. Ponder has a 77.9 rating and has tossed seven touchdowns compared to nine interceptions.
"I don't think there is any difference," Defensive Coordinator Dean Pees said. "There is always a difference with some guy's throwing motion or something like that, but it's the same offense. Whether Ponder is in there or Cassel is in there, it's [Peterson]. And then it's play-action off of that."