"Behind Enemy Lines" is a Thursday post on the Access Vikings blog. In advance of Sunday's Vikings-Titans game, Dan Wiederer of the Star Tribune interviewed Jim Wyatt, the Titans beat writer for the Nashville Tennessean. Here are three things you need to know ...

1 The Titans defense is a disaster.

Want some eye-opening statistics? Tennessee has given up 151 points in its 1-3 start, most of any team in the NFL. The Titans also rank second to last in total defense, giving up 421.5 yards per game.

Yes, the Titans have faced some pretty good quarterbacks -- Tom Brady, Philip Rivers, Matthew Stafford and Matt Schaub. But they've also allowed opponents to complete 75.3 percent of their passing attempts with 10 touchdown passes and only one interception.

"They're offering very little resistance whatsoever," Wyatt said. "And as a result, they've been falling behind early in these games and really not performing up to their potential."

Tennessee has six sacks through four games -- fifth worst in the NFL -- and no player has more than one.

"There's not a consistent pass rush," Wyatt said. "And they're not doing much extra to create pressure, either, by sending guys. They've played it safe going against the top-notch quarterbacks they've faced. But as a result, they've been so worried about getting burned by blitzing that they've just sat back and let teams pick them apart."

2 Chris Johnson showed encouraging flashes of brilliance in last week's loss at Houston.

After totaling only 45 rushing yards in Tennessee's first three games, Johnson showed his Pro Bowl potential by busting loose for 141 yards on 25 carries in Week 4. Johnson's struggles in the first three weeks occurred in part because the Titans fell behind and never committed fully to the run. But even when they did, Johnson got nothing going.

"He was indecisive in hitting the holes," Wyatt said. "And the blocking in front of him wasn't all that great. So then when they have a game like Sunday where they were so much better, it makes you wonder, 'Where the heck has that been?' I'm not sure if they've totally fixed things. But they looked like a different team and Chris looked like a different back."

As for the outside criticism that Johnson got fat and happy after signing a four-year, $53.5 million contract extension on the eve of the 2011 season, Wyatt doesn't think that theory has much validity.

"Chris is a hard-working kid and he's committed to football," Wyatt said. "And he's got a lot of pride in himself and what he's accomplished in the early portion of his career. I don't think it's fair to say he's all of a sudden taking it easy."

3 With Jake Locker out this week with a shoulder injury, 37-year-old veteran Matt Hasselbeck will lead the Tennessee offense.

Hasselbeck certainly isn't as multidimensional as Locker, but he offers a presence and is usually solid with his decision-making.

"Maybe that's what they need right now at 1-3 and needing a jolt of energy," Wyatt said. "They'll lose something with Hasselbeck in the mobility department. But maybe they make up for it with his leadership."

Hasselbeck was 17-for-25 for 193 yards in relief of Locker last week. He threw touchdown passes of 19 yards to tight end Craig Stevens and 11 yards to rookie Kendall Wright. But he also had two interceptions returned for touchdowns.