NFL Playoffs NFC Championship: Vikings @ Eagles
Minnesota Vikings @ Philadelphia Eagles
Lincoln Financial Field, Philadelphia, PA
January 21, 2018 3:40PM
Our power rankings framework has backed the Eagles since the Wildcard Round, despite its reliance on second-string QB, Nick Foles (Philly's starting quarterback, Carson Wentz, went down with a torn ACL in week 14). Our approach sees no reason to jump off the ATS bandwagon at present. Accordingly we are betting Eagles +3.5.
Going into the Divisional Round of the playoffs, it was easy to make the case that Foles was overmatched versus Matty Ice and the Falcons. At the end of the regular season, Ryan ranked #7 in the League by FootballOutsider's advanced statistic, Defense-adjusted Yards Above Replacement (DYAR). DYAR measures value of quarterback output (in yards) relative to a replacement level player and adjusted for situation and opponent. Ryan finished the regular season with a rating of 1,087 yards better than a replacement caliber QB, while Foles' DYAR rating was a below average -114 after week 17.
ESPN's better known QB or Passer Rating tells a similar story. This metric considers passing attempts, completions, yards, touchdowns, and interceptions. Per the graphic below, save 2013, Ryan's QB Rating has consistently ranked higher than Foles' (not shown: in 2017 Foles managed a passer rating of 79.5; 11.9 points below Ryan's score for the most recent season).
Regardless though of the theoretical disparity at the QB position, the Eagles bested the Falcons 15-10 -- largely due to a strong Philly defense that seemed to know exactly what the Falcon's wanted to do (as the epitome of Philly's defensive prescience, the Eagles claim to have known precisely the play the Falcons would attempt, down by 5 on a 4th down in the red zone, with a minute left to play). On the day, Ryan was held to a below average QB rating and the Falcons mustered only 10 points.
In the Conference Round, we think the gap between the QBs is much smaller. While the Vikings' Case Keenum enjoyed a terrific 2017 (ranking #3 by QB Rating and #4 by DYAR), Keenum is not exactly a rising star at his position. For instance, the 5th year QB's -183 DYAR score last year was good for 31st in the NFL among QBs attempting a minimum of 200 passes. Moreover, in limited action, Keenum was only modestly better than average by DYAR in 2015. We also note that over their common careers, Foles' average QB Rating bests Keenum's. Thus, we are not convinced that Keenum is consistently better under the Center than Foles.
Further, the Vikings' are likely to achieve below average success running the ball against the Eagles #3 rushing defense. Such a development is likely to materially disrupt Minnesota's comfort on offense, as the ground game is core to their strategy. Per the graphic below, the Vikings run the ball (as a percentage of all offensive plays) more than all but three NFL teams. MIN also ranks in the top-ten by rushing yards and rushing touchdowns.
In support of our thesis that Philly will contain Minnesota's rush attack, we point out that In the five games this year in which the Vikings faced elite run stoppers (defined as defenses that finished the year among the top-ten by DVOA), MIN has been held to below average gains on the ground four times. Also, the Vikings scored fewer touchdowns on the ground against the best rushing defenses than their average.
Fittingly, our power rankings framework makes the Vikings and Eagles to be pretty even on a neutral field. Specifically, we give the Vikings roughly a 1-1.5 point edge (on defense; we see the offenses and special teams as approximately dead even). After factoring in Philly's estimated home field advantage (which our approach estimates is between 2-3 points), we conclude that the Eagles plus the points is a play.
As an aside, we determine the value of home field via an optimization process based on the previous regular season's action. In our work, home field advantage is a constant (one value for all teams) established at the start of each season. However, other objective approaches suggests the comfort of home is worth 1.7-2 points to the Eagles. Using either estimate, as far as we can tell, there seems to be value with Eagles +3.5.
Separately, our computer simulation work highlights OVER 38.5 as a high conviction wager. Consistent with this forecast, we note the broad tendency for Vegas and/or the betting public to underestimate offensive output of strong defenses deep in the playoffs. Per Pro Football Reference, of the 15 NFL Conference Playoff games since 1990 that featured a total of 40 or less, the O/U is 10-4-1.
Fundamentally, the OVER is supported by our expectation for Minnesota to throw the ball more than usual Sunday, as an adjustment to Philly's stifling rushing defense (MIN is #18 running the ball by DVOA, while PHI is #3 defending the rush). Such a happening would not be unprecedented. In the Vikings' five regular season meetings with top-rated rushing defenses (by DVOA), Minnesota's utilization of the run slipped from top-5 to about average. Sunday, an increased emphasis on passing could facilitate a beefier Vikings scores, or, better yet, yield points to the Eagles, whose defense ranked #4 in touchdowns scored. Either way, the prospect of a greater dependence on passing syncs with our OVER bet.
Bottom line: Back the home dogs to cover, and the OVER.