San Francisco 49ers (5-9) at Arizona Cardinals (8-6)
The 49ers lost last week in upset fashion to the Cowboys and that seems to have caused the public and the oddsmakers to sour on them, with this line shifting from Arizona -3 on the early line last week to Arizona -5 this week. That might not seem like a huge line movement, but about 1 in 5 games are decided by 3-5 points, including 1 in 6 games by exactly a field goal, so it’s definitely a significant movement. It’s not surprising that line movement happened, as the public views the Cowboys as one of the worst teams in the league and the 49ers just lost to them, but I think it’s an overreaction, as significant week-to-week line movements tend to be.
Not only are the Cowboys a little underrated (the season long stats don’t show they’ve improved significantly in recent weeks), but the 49ers outplayed them for most of the game, winning the first down rate battle by 8.71% and losing primarily because of a -4 turnover margin, which tends to be highly inconsistent on a week-to-week basis. Teams with a turnover margin of -4, on average, have a turnover margin of -0.01 the following week and, as a result, cover at a 52.4% rate as underdogs.
Last week was kind of a microcosm of the 49ers season, as they actually rank 5th in schedule adjusted first down rate differential at +2.93%, but are just 5-9 because of a 2-4 record in games decided by one score, a -11 turnover margin that is 2nd worst in the NFL, and a -4 return touchdown margin. First down rate differential is a much more predictable and predictive metric than the other metrics, which are largely unpredictable week-to-week, so, while the 49ers aren’t the 5th best team in the league, they’re better than their record suggests, especially when you consider they’ve faced one of the toughest schedules in the league.
This line movement can also be somewhat explained by the 49ers’ injuries, as they will be without two of their top remaining defensive players in cornerback Richard Sherman and safety Jimmie Ward this week and they also lost backup quarterback Nick Mullens, who had been starting in the absence of Jimmy Garoppolo, and starting running back Raheem Mostert, but 3rd string CJ Beathard isn’t really a downgrade from Mullens, the 49ers are deep at running back behind Mostert, and they will also welcome back a pair of key players in tight end George Kittle and cornerback Jason Verrett, the latter of whom has actually outplayed Sherman this season prior to missing last week’s game against the Cowboys. Overall, my calculated line is still at Arizona -3 at the highest, especially when taking into account that this is essentially a neutral site game, with the 49ers sharing the Cardinals stadium for the past month and neither team being allowed fans in the stadium.
On top of that, the Cardinals are in an awful spot for several reasons. For one, they’ve already beaten the 49ers once this season and might not take them as seriously the second time around, especially with the 49ers in a more diminished state right now than they were in that game and with the 49ers coming off of last week’s loss. Divisional home favorites cover at just a 42.6% rate in a same season, regular season rematch against a team they previously beat in upset fashion, including 40.5% as home favorites of 4 points or more.
The Cardinals also have a tougher game on deck against the Rams and favorites cover at just a 42.4% rate at home against a sub-400 divisional opponent before going on the road and facing a divisional opponent with a record better than .600. On top of that, this is close to a must win game for the Cardinals, who currently have a loose hold on the NFC’s 3rd and final wild card spot. You might think that because this is a must win game that the Cardinals will rise to the challenge against a team with nothing real to play for, but that’s actually the opposite of what typically happens in this situation, as teams with a 51%-65% winning percentage cover at just a 42.3% rate in weeks 16 and 17 against a team with a sub-.500 record. The Cardinals could still pull out the win, but the most likely result is them winning by 1 or 3 points and I would be surprised if they were able to win this one easily, so the 49ers are worth a significant bet.
Arizona Cardinals 24 San Francisco 49ers 23
Pick against the spread: San Francisco +5