Eden Prairie, MN (My Sportsbook) - Minnesota Vikings quarterback Gus Frerotte is doubtful for Sunday's tilt with the Arizona Cardinals with a lower back injury suffered in last week's win against the Detroit Lions.

Frerotte sat out both Wednesday and Thursday's practice sessions and was limited Friday. Tarvaris Jackson, who began the season as Minnesota's starter, will get the call under center should Frerotte be unable to go Sunday.

The injury occurred when Frerotte had a pass attempt at the line in the second quarter knocked into the air, and Detroit's Corey Smith came down with the ball. Frerotte tackled Smith after the pick and was hurt on the play. Frerotte went 7-for-10 with 70 yards and two interceptions in the game before leaving.

Jackson took over and finished the game 8-for-10 with 105 yards and a score, as the Vikings improved to 8-5, maintaining its slim lead over Chicago for first place in the NFC North. The Bears moved to a half-game back of Minnesota after knocking off the New Orleans Saints on Thursday to start the Week 15 schedule.

In addition, defensive ends Jared Allen and Brian Robison are both questionable for Sunday with respective knee injuries.