New England Patriots star tight end Rob Gronkowski is reportedly set to undergo back surgery later on this month following a successful, fourth operation on his left forearm. Gronk is on the mend, but the issue becomes whether or not he will miss any time. The next question is, if so, then how much time will the Patriots be without Gronkowski? Some believe that Gronk will be placed on the PUP list and miss the first six weeks of the season, while others think Gronk can make it in time.
I’m not here to talk about how long I think Gronkowski will be out or what the Patriots should do with him (specifically, with regards to the PUP list). However, my goal in writing this piece is, mainly, trying to do what one might call a “fun little exercise”. Using advanced statistics, I want to try and pinpoint what the impact of losing Gronkowski for a set amount of time would be. It’s just an interesting look at Gronk’s impact, but the disclaimer is that it is a very rough look. Not only do these numbers not take into account Gronkowski’s extraordinary blocking (it’s too hard to quantify blocking in numbers), but it’s also tough trying to match up all the variables. But I am going to try my best, and I think we can get some good discussion rolling. There isn’t much to talk about football-wise these days, and we can actually have some hard, football talk about Gronk instead of speculating about his injury.
Despite playing in 12 games, Rob Gronkowski was fourth in the league last season in WPA with 1.36, as calculated by Advanced NFL Stats. Gronkowski, in fact, played in the least games of any tight end in the rankings all the way down to 18. Who was 18th in total WPA last season? Well, none other than his fine teammate Aaron Hernandez.
And WPA per game? Gronk was third behind Tony Gonzalez and Jason Witten. This is why I said these statistics are rough, because Gronkowski was still clearly the best TE in the league last year when healthy. He was actually in the clear lead in EPA per play (expected points added, whereas WPA is win probability added) and was second in total EPA behind Gonzalez. Now why do I use WPA instead of EPA when I am an admittedly a bigger fan of EPA (not just in this case but in all cases). Well, because this is only meant to be a rough estimate of value, and it’s too hard for me to try and transpose points to wins. I prefer EPA to WPA, but this piece is confusing enough in the stats department and is already creeping up on 470 words.
Gronkowski’s replacement is set to be Jake Ballard, who was a damn fine tight end in the 2011 season. Since Ballard didn’t play last season, I’ll have to use his 2011 season and try to cross-compare it to Gronk’s WPA per game in 2012, then normalize it. Ballard will probably be better than he was in 2011, but I’m not going to try and boost his stats and speculate; I just want to deal with the raw data.
Including the playoffs, Ballard was worth 1.09 wins in WPA in 18 games for the New York Giants. That was actually good for eighth in the league, but his WPA per game in 2011 was barely more than half of Gronk’s total (.11 to .06). Those numbers might be rounded, so I am going to average my own WPA per game totals. Gronkowski, by the way, was the clear league leader in 2011 in all stats (that probably went without saying), but I am going to use his visibly worse 2012 numbers. Why? They are more recent and would better take into account any ill effects of injury.
Over a 16 game season by using the process I outlined above, Gronkowski would be worth 1.81 wins and Ballard would be worth 0.94 wins. That’s not even a one win difference. Now that isn’t taking into account blocking, and that’s actually almost a worse-case scenario for Gronk. If I used his 2011 numbers, he would be worth 2.85 wins and nearly two wins more than Ballard. If I want to take into account blocking and also get a generally more accurate result overall, I would go somewhere in between and view Gronk has being about 1.5 wins more than Ballard (I know, I know…I said I wasn’t going to speculate, and I didn’t to this point- just want to expand on some stuff for those interested).
But 1.5 wins is a big difference over 16 games, since 16 games isn’t really a long time when dealing with those numbers. By extension, 1.5 wins represents about 10.7% of the NFL season in games, and that has some significance. I mean, there is a legitimate difference between being 11-5 and 10-6 or 9-7 and 8-8, so one win does certainly mean something.
However, it is just one win (or 1.5, depending on how you look at it), and it isn’t like Gronk would be missing 16 games- he might not even have to miss six. If the Pats do place him on the PUP list, then (1.5 divided by six), they would lose a quarter of a win. You can live with that, and it might be worth it when given the chance of resting Gronkowski. That’s all perspective, but it’s interesting to use the numbers to try and get a better perspective on raw data. It is rough, yes, but it is better than mindlessly worrying. 0.25 wins isn’t insignificant, but it isn’t crushing. Gronkowski missing some games isn’t going to crush the Patriots chances of winning a Super Bowl (I’ll stick with the 1.5 win scenario outlined above, though), but that’s only if those games are in the regular season. While those games still have bearing, those numbers become a bit more urgent in the postseason or down the stretch of the regular season. It’s not because the regular season games are insignificant (I would never make that blanket statement), but rather because there are less chances to rectify losses and there is more urgency in the postseason; I am sure everyone sees that.
So what is your take on the numbers and the impact of losing Gronkowski? If you hate statistics, this post was probably not for you. I just wanted to put some stats into the equation, talk some football, and not talk about how severe the injury is, but rather what his impact is to the Patriots. He is a very important part of the offense (3.38 WPA in 2011 is just a ridiculous total, for those well-versed in that stuff), but Ballard is good enough to where the Patriots wouldn’t be devastated by losing Gronkowski for a period of around six games. But if that stretches into an entire season of Gronk (which I definitely don’t anticipate happening, I don’t even think he’ll miss six games at this juncture), then we’re in trouble. But, since that almost certainly won’t happen, the Patriots are going to be fine.
Hope for the best, prepare for the worst, but quit needlessly worrying and getting too cynical. The big thing is getting him back healthy when we need him, because he is such an incredible talent. He blocks like an OL, catches like a WR, and the stats also love him. Man, 3.38 wins in 2011. Even if that’s a rough estimate, that’s still incredible. Hell, with his blocking, that might even be closer to four.
You can follow Joe Soriano on Twitter @SorianoJoe.