The 2008 New England Patriots season sucked, at least by the standards that we’re used to in New England. It was 1 of 2 seasons out of 15 when they didn’t make the playoffs, an 8-8 team played January football but the 11-5 Pats didn’t, and we got to watch Tom Rrady for exactly 2 drives all season.
But we learned some things about the Patriots. We learned that anyone who thought that Belichick’s success had been entirely due to Tom Brady was a moron. We also got to see a good estimate of how good a quarterback has to play for the Patriots to still be a playoff team. They may not have made the postseason that year, but an 11-5 record in a season with inflated records in the AFC East is a pretty good indicator of where the line of demarcation is for whether or not a team makes the playoffs.
Therefore, we need Jimmy garoppolo to measure up to Matt Cassel in order to the Pats to stay on a playoff pace. They could still make the postseason if Garroplo was a lot worse and the Pats went 1-3 without Brady, because TB12 is TB12. But given how important homefield advantage is for the Pats, we need to hope for more.
Matt Cassel put up almost 3700 yards, 21 TDs, 11 picks, a 63.4% completion percentage, an 89.4 passer rating, and he threw on 270 rushing yards for good measure. Cassel also averaged 7.16 yards per passing attempt, and the Pats as a whole averaged 6.7 Garoppolo is only slated to play a quarter of the season, so we can knock those numbers down to 925 yards, 5 TDs, 3 INTs, and the same 63.4% and 89.4 completion percentage and passer rating, respectively.
However, we need to account for the fact that the quarterbacks and passing attacks have gotten a lot better in the NFL over the past 8 years. In 2008, the median yards per team passing play was 6.4, and in 2015 it was 6.7. The median passing completion percentage in 2008 was 60.45%, while it was 63.08% in 2015. That means that 2008 New England was about 0.3 yards per passing attempt better than league average with Cassel, and Cassel put up a completion percentage that was about 3% better than league average.
So let’s say Garoppolo performs beats league average by the same margins that Cassel does. That would put the Pats at 7.0 yards per passing play and a 66.4% completion percentage. Those seem like some lofty standards, but that’s where the NFL passing game is right now.
Garoppolo had a 72.7% completion percentage, and the Pats averaged 7.8 yards per passing play. That means that Garoppolo is already ahead of pace from what Matt Cassel laid out, which is something I think we all expected anyway.
Really, though, why does it matter how much better Garoppolo is than Cassel? If The Pats can just get enough good play and enough luck for New England to go 3-1 without Brady, isn’t that all that matters?
Not so much. Matt Cassel provides another barometer for Garoppolo and the Patriots: The Kansas City Chiefs traded the 34th overall pick for Cassel, and Cassel was a former 7th rounder who still carried doubts about whether or not he would succeed without an amazing team like the Patriots around him. Bill Belichick will look to trade Garoppolo after the season — when Jimmy G has 1 year left on his deal — and he’ll want a bigger return than the 34th pick.
How much better Garoppolo plays than Cassel determines just how high that return is. If Jimmy G continues that line of 7.8 yards per passing play (and 8.0 yards per actual pass attempt) and keeps completing more than 7 out of every 10 passes, then 2 first round picks is in play as far as a trade haul. Matt Cassel set the trade market for a promising backup of Tom Brady, and it looks like Jimmy Garoppolo has a good shot of obliterating that market.