Quarterback
There was a lot of concern in the fantasy football community about QB Tarvaris Jackson and how he might hold back the Vikings powerful rushing game. This may prove to be true, but not for the reasons initially believed. Jackson has looked very sharp during the limited time he has been able to make it onto the field; however, a bruised knee injury kept him out of the last preseason game. Jackson has suffered from a variety of injuries during his pro career, missing a lot of games and causing some in the Vikings organization to question his toughness. He is reportedly still feeling some pain in the knee when he moves laterally, but should be ready to play on opening day.
Backup QB Gus Frerotte looked exactly like a journeyman reserve quarterback. He is capable of making some good throws, but his decision-making is just a little slower than your typical starting quarterback in the NFL. This lead to him getting sacked or hurried by the Steelers on passing plays where the Viking offensive line gave him enough time, but he didn’t pull the trigger and get rid of the ball fast enough. If Jackson can’t take the field, the Vikings offense could be in serious trouble.
Running Back
RB Adrian Peterson started the last couple of Vikings preseason games, but hasn’t shown much, carrying the ball 8 times for 30 yards against the Ravens and 12 times for 21 yards (with a one-yard TD) against the Steelers. Peterson is going to need Jackson playing QB to help him succeed.
RB Chester Taylor has performed similarly as Peterson, rushing for 23 yards against the Ravens and 5 yards against the Steelers. Peterson’s one-yard TD run may show that Taylor will not be a "goal-line vulture" this season.
Wide Receivers
WR Bernard Berrian has been suffering from some form of turf toe and didn’t play in the last two Viking preseason games. The Vikings are probably being overly cautious with their new free agent acquisition, but since he hasn’t had much time to adjust to a new quarterback, it is likely that Berrian will get off to a slow start this season.
WR Sidney Rice, with a virus, also missed the last preseason game. Much like Berrian, Rice could have really used some extra playing time with his quarterback and might start the season slowly.
Tight End
The Vikings TE situation, from a fantasy perspective, is as bleak as possible. TE Visanthe Shiancoe has been the leading received from the TE corps, with three catches in the past two weeks.
Kicker
K Steven Hauschka has been kicking for the Vikings to help save veteran K Ryan Longwell’s leg. Longwell was the kicker during the Steelers preseason game, made very FG and extra point attempt, and is clearly the Vikings guy.
Defense/ST
The Vikings D/ST managed to put a lot of pressure on the Steelers QBs; however, this might not be saying much, as the Steelers offensive line has really struggled in pass protection the past two years. Throughout the preseason, the run defense has performed exactly like the NFL’s top-ranked run defense should. Dominantly.
The Vikings were one of the top scoring fantasy defenses last season due to 9 TDs. I believe a portion of this was simply luck; expecting them to repeat that performance might be too much.