As the Vikings prepare for Sunday's game with Detroit at Ford Field, we asked Dave Birkett, the Lions beat writer for the Detroit Free Press, to give us his up-close-and-personal scouting report. Here are four things you need to know … 1) Quarterback Matthew Stafford will do everything within his power to play Sunday.Stafford couldn't finish last week's wild 44-41 overtime loss in Tennessee, sidelined in the fourth quarter by a leg injury that bothered him last week in practice and was aggravated as he tried to chase Titans cornerback Alterraun Verner during his 72-yard fumble return.The Lions are remaining mum on Stafford's status for Sunday and won't have to put an official label on him until Friday afternoon. The Vikings, of course, will prepare as if Stafford has the green light. And even if it's a yellow light, Birkett expects the Lions signal caller to be ready -- even if the specifics of Stafford's injury remain quite mysterious."Just knowing who Matt is, I think he'll try to give it a go," Birkett said. "Last year, he played with a broken finger for three games. He played with a bad ankle sprain. He missed a lot of games early in his career and I think he'd just assume not miss anymore. And they have a bye in Week 5. So I think he understands that if he can gut through this one, he'll have an extra week to heal up."As far as Stafford's play through the first three weeks, the downfield fireworks haven't exploded as often as they did last year. But he's been making high percentage throws pretty consistently.As for the three interceptions he threw in a season-opening win over St. Louis?"Those were poor decisions, trying to force some things where they shouldn't have gone," Birkett said. "But other than that, I think he's played within the game plan. And he hasn't lost anything from a skill standpoint."If Stafford weren't able to play, Shaun Hill would get the nod. He went 10-for-13 for 172 yards in relief last weekend, throwing a 46-yard Hail Mary touchdown to force overtime. Hill isn't on the same level as Stafford. And while he is an above-average No. 2 quarterback, Stafford's absence would be big.2) Defenses continue to surround Calvin Johnson the way the secret service surrounds President Obama.If you see Johnson in single coverage this year, more times than not, it means somebody blew an assignment. The Rams, 49ers and Titans all focused their defensive game plan around containing Johnson. Which makes it all the more remarkable that he still leads the league in receiving yards with 369 through three games.Johnson registered 158 of his 164 receiving yards last week after halftime.Said Birkett: "What's been happening is most defenses are playing two deep safeties and using two and three guys on Calvin. The Titans didn't blitz. They didn't do anything but drop the safeties 15 or 20 yards back and just sit two guys on Calvin. … This is just the way to stop the Lions offense. Stop Calvin first. It limits their explosiveness. All of a sudden they have to drive seven, eight, 10 plays to score. And that puts the onus on Stafford to make the right decisions and on the running game to pick up chunks."3) The Lions must rally after last weekend's 44-41 overtime loss in Tennessee.How's this for wild? Detroit gave up a 65-yard punt return touchdown on a trick play and a 105-yard kickoff return score. They watched the Titans return a fumble 72 yards for a score. They surrendered two passing touchdowns of more than 60 yards. They rallied from 14 points behind with 30 seconds to play to force overtime on a 46-yard Hail Mary touchdown pass and then lost in overtime when a blunder by center Dominic Raiola resulted in a snap that shouldn't have happened and a loss of 1 yard on a fourth-and-1 play that was the game's last.Said Birkett: "It was the wildest, craziest game I've ever seen, no doubt."It was also a loss that dropped Detroit to 1-2, which can put a good team on edge this early in the season. But the Lions are retaining perspective."Internally I don't think they've lost any hope," Birkett said. "I think last week's game was definitely a wake-up call. Because the Titans are a team they should beat. But they're home this week against Minnesota and they're confident with where they're headed. No one is or should be counting the Lions out just yet. But this week is an important test for sure."Most troubling last Sunday was Detroit's inability to fluster Titans quarterback Jake Locker, who threw 42 passes, was never sacked and was hit just once. That left a mediocre secondary with too much responsibility. And the Lions defense was badly disjointed on a 65-yard Locker to Tommie Campbell TD pass and a 71-yarder to Nate Washington."The secondary has been a continuous problem for this team," Birkett said. "They just haven't invested much in the back end. So when they don't get any pressure up front, then they're really in trouble."4) Tailback Mikel Leshoure had a 100-yard day in his NFL debut.Drafted 57th overall in 2011, Leshoure had last season wiped away when he tore his Achilles tendon. Then he was suspended for the first two games of this season after a pair of offseason marijuana-related arrests.Yet, Lions coach Jim Schwartz and offensive coordinator Scott Linehan made sure to make Leshoure a focal point of their game plan in his debut last weekend, giving him 30 touches. Leshoure had 26 carries for 100 yards, including a 1-yard touchdown. He added four catches for 34 yards."Still plenty of room for improvement," Birkett said. "But he's definitely injected at least a little bit of life into the running game. He's a guy who defenses have to account for because he doesn't get thrown for losses much. He's always falling forward, picking up an extra yard here and there."Leshoure can be a bruiser as a back and has decent athleticism and hands."He's not shifty as Jahvid Best. He's not that elusive," Birkett said. "So I wouldn't expect any 80 yard gains. But he's always getting you 4 yards and making positive yardage, which is something the Lions haven't always had."