A month ago, the Ravens had the NFL's top-ranked passing defense. Now, that part of their game has become a bit of a liability.
Since halftime of the Patriots game two contests ago, the Ravens' defense has allowed 558 passing yards and five touchdowns through the air. They've had issues with missed tackles, and are coming off a frustrating performance against the Bills, who entered their game in Baltimore throwing for only 144 yards per game, second-to-last in the NFL.

This Sunday, things won't get much easier on the Baltimore secondary, as they'll have to face Brandon Marshall, the Dolphins' two-time Pro Bowl wide receiver who is currently fourth in the NFL in receptions.
Marshall is big (6-4, 230), physical, and has great speed and run-after-the-catch ability for a guy his size, making him one of the more difficult receivers in the league to cover.
Don't believe me? Ask those who will have to defend him this Sunday.
"Oh, he's one of the top guys in the NFL," cornerback Fabian Washington says. "He's got it all."
"He runs the entire route tree out there," head coach John Harbaugh said. "He runs quick passes and does everything downfield. He's a very good route-runner for a big man. When he runs the underneath stuff, it's always a catch-and-run idea."
It's that catch-and-run stuff that the Ravens will have to focus on this week. After missing countless tackles against Buffalo in their last game, the Baltimore defense will face a receiving corps that excels at picking up yardage after having the ball in their hands.
If the Ravens hope to get off the field on defense, they'll have to take good angles to the ball, be in good position defensively, and wrap up Marshall and fellow Dolphins wide receiver Davone Bess - another speedster - when they have the ball in space.
"One of the biggest things in their passing game is catch and run," Harbaugh said. "The throws to Bess and Marshall, especially - and a lot of times to the backs and the swing routes - are catch-and-run ideas. They're an extension of their run game, and we're going to have to do a great job tackling those guys, because that's a big part of what they do."
While Bess is a smaller guy at 5-10, 190, making him easier to wrap up, the Ravens will have a bigger problem bringing down Marshall.
The five-year veteran towers over those in the Baltimore secondary, which features no cornerback taller than 5-11, and no safety taller than 6-foot. Needless to say, tackling has been an emphasis for the Ravens in practice this week.
"We have to be better about that," said cornerback Chris Carr. "We can't have another performance like we did against Buffalo. These guys are hard to bring down, and so we've got to focus on the fundamentals and get them, especially [Marshall], to the ground."