Greg Cosell's Look Ahead: Breaking down the Lions' top-ranked defense

The Detroit Lions’ defense, leading the NFL in fewest yards allowed, can be exploited if you work their secondary. The problem with that plan is the line and linebackers are so good, it’s tough to get to the secondary.

The Lions might have the best front in the NFL. You can’t consistently throw with functional space against their pass rush, which was a problem for the New Orleans Saints last week. The Lions face the Atlanta Falcons on Sunday, and Atlanta's offensive line won’t be able to handle Detroit’s front.

[Join FanDuel.com's $2.5M Week 8 fantasy league: $25 to enter; top 21,905 teams paid]

Up front for the Lions, Ezekiel Ansah is one of the most athletic defensive ends in the NFL; he has a chance to be an outstanding player with some more experience. Ndamukong Suh will play defensive end in the nickel package, and he can rush the passer from inside or outside. Jason Jones has always been  overlooked wherever he has been; like Seattle’s Michael Bennett he can play end in the base defense or tackle in sub packages and is a good pass rusher. One other player who stands out in the front six in the nickel packages is linebacker Tahir Whitehead. He got a chance to play every down after Stephen Tulloch’s season-ending knee injury, and he has proven himself to be a three-down player with excellent sideline-to-sideline range. He flashes every week.

The biggest play of the Lions’ win last week showed how the front is helping the secondary. On a third-and- 9 for the Saints in the fourth quarter, with the Lions trailing 23-17, Detroit ran “man free lurk.”  Quarterback Drew Brees looked right at safety Glover Quin, so he knew Quin was the lurk defender. But defensive end George Johnson beat left tackle Terron Armstead, and forced Brees to move up. Brees lost clarity and threw it right to Quin, who was cutting in front of Marques Colston.

The Lions do a good job understanding their defensive backs’ strengths and putting them in the right positions. There are still weaknesses in the secondary, and a good passing offense could exploit that if they can protect well. The problem is, the front is so good that rarely happens.

Ryan Tannehill shines

Miami Dolphins quarterback Ryan Tannehill has played really well the last couple weeks. The Dolphins are doing a lot more with him running, using some read-option looks. Tannehill can do that; he was a receiver early in his college career and is a good athlete. They’re using a great mix of Tannehill under center and in the shotgun.

One play stood out from last week’s win against the Chicago Bears. From the 10-yard line, the play was designed to be a quick slant off motion to tight end Charles Clay, with a complementary drag route by Brian Hartline to eat up linebacker D.J. Williams and create a passing lane for Clay.

Tannehill didn’t get a clean look at Clay and came off it to the other side of the field. Mike Wallace ran hard on the back side as if his route was live, and Tannehill showed outstanding trust, anticipation and ball placement to get it to him for a 10-yard touchdown.

Zach Mettenberger to start

The Tennessee Titans are planning on starting rookie Zack Mettenberger at quarterback this week. I like Mettenberger.

In college at LSU, he was a confident, aggressive pocket passer. He was an easy thrower with an NFL arm. He can drive the ball downfield. He had a few accuracy issues, but he had the physical tools to be a good pocket quarterback, including the fact that he was oblivious to pressure in the pocket.

He showed a lot of these things in the preseason, when he led the NFL in passing yards. He was still decisive with his reads and throws, and showed better accuracy too. He was very good in a muddied pocket because he feels but never sees pressure. He looked good in the preseason, and now we get to see if all of his skills translate in the regular season.

Rams change backs

The St. Louis Rams made a move to go with rookie Tre Mason as their featured tailback, ahead of Zac Stacy, who had 973 yards last season. Mason is an upgrade.

Mason runs with a naturally low pad level, which gives him power as an inside runner. He’s much quicker and more explosive than Stacy. Mason also showed patience, vision and outstanding short-area burst.

Stacy played just one snap against the Seattle Seahawks. His days as the Rams’ featured back are over. Mason is a better runner.

- - - - - - -

NFL analyst and NFL Films senior producer Greg Cosell watches as much NFL game film as anyone. Throughout the season, Cosell will join Shutdown Corner to share his observations on the teams, schemes and personnel from around the league.