For a look at the big storylines in this Sunday's NFC Championship Game from the opposing team's vantage point, Mike Wobschall from Vikings.com provides insight on quarterback Case Keenum, the top-ranked Vikings defense, and the under-the-radar players to watch. You can follow Mike on Twitter **@Wobby**.*

1. What has impressed you the most about Case Keenum's performance this season?

Mike Wobschall: The most impressive aspect of Keenum's season has been his ability to keep performing well despite the presence of Sam Bradford and Teddy Bridgewater on the depth chart. Both Bradford and Bridgewater have played well for Mike Zimmer and one can understand why the Vikings' head coach may have felt compelled to get one of them back in the lineup. And Keenum knew that. But Keenum kept playing, and he kept playing well. Every week. No longer is the Vikings' offense being dragged along by the defense. The offense is a winning part of the equation, and Keenum's presence as the starter is a key reason why.

2. How did the offense stay on track after Dalvin Cook's injury?

Mike Wobschall: I'd be remiss to not mention offensive coordinator Pat Shurmur here. Prior to the season, I would've listed Sam Bradford and Dalvin Cook as the two most important players on the Vikings' offense, and Shurmur had lost both of them for the season before the end of Week 4. Yet the Vikings were still able to score 23.9 points per game. Jerick McKinnon and Latavius Murray stepped up big time in Cook's stead. In fact, the Vikings ranked No. 4 in the NFL this regular season in rushing yards by a tandem. McKinnon's ability to run and catch out of the backfield and Murray's physicality and short-yardage/goal-line prowess were vital for the Vikings' offense this season.

3. This team started 5-0 last year before missing the playoffs. What allowed it to take the leap in 2017?

Mike Wobschall: Several factors combined to help the Vikings take a big step forward in 2017. One I'd point to for sure is the performance (and health) of the offensive line. The Vikings signed free agents Riley Reiff to play left tackle and Mike Remmers to play right tackle and then they drafted center Pat Elflein. These three new faces changed the offensive line and teamed with holdovers Nick Easton at left guard and Joe Berger at right guard to give the Vikings a solid starting five. Also, Rashod Hill and Jeremiah Sirles served as key reserves to give the Vikings depth at a couple moments this season when starters were lost; Easton is on the Injured Reserve list now.

4. Mike Zimmer's been known for his A-gap pressures, but there haven't been as many this season. How is the defense still able to rank No. 1 in points and yards allowed?

Mike Wobschall: The calling card of the Vikings 'defense in 2017 was its performance on third down. Opponents converted on only 25.2 percent of third downs this season, the best mark recorded in NFL history. The Vikings allowed a total of 51 conversions on 3rd downs - 51! That's an average of 3.2 third-down conversions per game. A big key to this success on third down was the Vikings' improvement in rushing defense, where they jumped from No. 20 (106.9 yards allowed per game) in 2016 to No. 2 (83.6) in 2017.

5. Who is an under-the-radar X-factor on offense and defense for Sunday?

Mike Wobschall: On defense, it's the status of safety Andrew Sendejo. He's an easily forgotten name on the Vikings' defense, but do not underestimate his importance to what Zimmer likes to do because of his synergy with fellow safety Harrison Smith and the rest of the defense. Sendejo was knocked out of the game last week and is in concussion protocol as the week of practices began.

On offense, it's Remmers. He'll likely start at left guard for the second consecutive week and the second time this season. I anticipate he'll look even better this week than he did last week with a game and another week of practices under his belt. With the Eagles' team speed on defense and the use of the Wide 9 technique, it will be interesting to see how much success the Vikings can have running between the tackles. Yes, Philadelphia has the NFL's No. 1 run defense and Fletcher Cox is a monster in the middle, but it's not easy to run wide on the Eagles, either. The ability of Remmers and the rest of the interior offensive line – plus fullback – to create running room in the middle will be key in this game.