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5 things: Vikings must win turnover battle in London

Turnovers could be big in Sunday's duel in London between Minnesota and Pittsburgh.

EDEN PRAIRIE, Minn. -- The Minnesota Vikings are the home team this week against the Pittsburgh Steelers.


Of course, the game is in London's Wembley Stadium, not the Metrodome. After last week's loss at home to the Cleveland Browns, Minnesota knows there is one possible difference being overseas in the United Kingdom.


"We won't get booed at home, let's put it that way, if we don't play well," Vikings defensive end Jared Allen said. "I guess that's a plus."


Minnesota and Pittsburgh will each be looking to earn their first win of the season after disappointing starts. Here are five things to watch for in Sunday's game:


1. Storming the Cassel


Many of the boos last week were directed at Vikings' quarterback Christian Ponder, who apparently played through a fractured rib. Minnesota is making a change at quarterback this week, but it's because of the injury and not production. Backup Matt Cassel, the veteran signed in the offseason, will start Sunday against the Steelers.


Pittsburgh has a good scouting report on Cassel. Steelers offensive coordinator Todd Haley coached Cassel in Kansas City. The Chiefs released Cassel this offseason after he lost his starting job with 21 interceptions in his 18 games the last two seasons.


Ponder was the 30th-rated quarterback in the NFL this season. And Minnesota has to hope it sees more of the Cassel that was named to the Pro Bowl in 2010, when he threw for 3,116 yards, 27 touchdowns, seven interceptions and had a career-best 93.0 quarterback rating.


2. Takeaways without turnovers


Cassel acknowledged the need to protect the ball when he talked to reporters Friday after learning he would be the starter. Turnovers were a big reason he lost his job in Kansas City and is also one of the biggest concerns regarding Ponder right now. The Vikings have taken the ball away at a pace they haven't done in several years. Minnesota has 10 takeaways this season, which ranks tied for second in the league. But the Vikings also have 10 turnovers of their own.


Pittsburgh has been in a similar situation, at least offensively. Pittsburgh has nine turnovers, the third-highest total in the league. But the defense hasn't bailed out the offense and maybe gives Cassel and Minnesota an edge this weekend. The Steelers are the only team in the league that doesn't have a takeaway this season on defense.


3. Preventing the prevent


The Vikings have had their issues on offense this season, but rank seventh in the league in scoring. The defense has taken the ball away, but has given up chunks of yardage and failed in late-game situations. Minnesota has lost the past two games in the final minute and defensive lapses have been the bugaboo in letting Chicago and Cleveland work their way down for game-winning drives.


The Vikings' defense had turned around in the second half of both games until those final drives and maybe lost a bit of aggressiveness. Pittsburgh quarterback Ben Roethlisberger has a knack for extending plays, so Minnesota will need to be sound on Sunday, especially in the secondary without injured starters Chris Cook and Jamarca Sanford. Marcus Sherels is expected to start for Cook and Andrew Sendejo will fill in for Sanford.


4. Protection and holes


Pittsburgh's defense hasn't taken the ball away, but it's also limited yards, ranking fifth in the league. There is plenty of blame to go around, but Minnesota's offense can't perform to its capability without improved play from the offensive line. The line has been, perhaps, the most disappointing aspect of the offense, unable to open holes in the running game for Adrian Peterson and not giving Ponder the chance to get comfortable in the pocket.


The Steelers have allowed the 11th most rushing yards in the league, likely a sign of trailing in games. They've allowed 3.3 yards per carry, which is tied for fifth-best in the NFL. Against the pass, Pittsburgh's defense has only three sacks on the season, tied for the lowest total in the league.


5. Getting Peterson going


One aspect that will help Cassel -- and Ponder if he comes back as the starter -- is getting Peterson and the running game going. Part of that will be on the offensive line, but Peterson and the Vikings do get Pro Bowl fullback Jerome Felton back this week.


Felton showed his worth last season, leading the way for Peterson's 2,000-yard season. He sat the first three weeks because of a suspension. He's back this Sunday and Minnesota has to hope his return will help the running game return to the explosive unit it was last season.


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