Fantasy football projections: Steelers vs. Vikings features Ben Roethlisberger, Antonio Brown and Adrian Peterson

The Week 4 matchup between the Pittsburgh Steelers and the Minnesota Vikings features two teams no one thought would be winless facing harsh times as they head to London to play one another. We've got all fantasy projections for you courtesy of numberFire.

With Rashard Mendenhall moving to the Arizona Cardinals in the offseason and rookie running back Le'Veon Bell sidelined due to a foot injury suffered in the preseason, the Steelers are averaging an AFC-worst 51.7 yards rushing per game. The black and gold are hopeful that Bell will start against the Vikings and give quarterback Ben Roethlisberger a more balanced attack to work with on the offensive side of the football.

One offensive player who is starting to step up for the Steelers is wide receiver Antonio Brown, who had the best game of his career in Week 3 against the Chicago Bears. Brown caught nine of the 13 passes thrown his way and finished with 196 receiving yards and two touchdowns.

Quarterback Christian Ponder fractured his ribs in the Vikings' Week 3 loss to the lowly Cleveland Browns. Before the injury, Ponder averaged 230 passing yards a game and had only managed to throw two touchdown passes compared to four interceptions. As a result of his injury, Matt Cassel will make his debut with the team. Cassel signed with the Vikings in the offseason after four dismal seasons with the Kansas City Chiefs.

If there is any saving grace in the Vikings offense at all in Week 4, it will come in the form of Purple Jesus himself, Adrian Peterson. After promising to break Eric Dickerson's single-season record for rushing yards, Peterson is averaging close to 40 yards less per game this year than he did last season. For any other running back that would be bad news, but for a monster athlete like Peterson it means that he still averaging over 93 yards per game.