The Miami Dolphins selected Tua Tagovailoa with the fifth pick in last year’s NFL Draft. One pick later, the Los Angeles Chargers selected Justin Herbert. Now, both of their rookie seasons are over, and the two young quarterbacks find themselves in dramatically different positions. Herbert is a likely candidate for Rookie of the Year, while some have already begun to wonder if Tua is a bust. However, the data shows that there are more similarities between their debut seasons than you might think.
Justin Herbert has a clear edge over Tua Tagovailoa in the box score
Looking exclusively at the two quarterbacks’ traditional statistics, it’s easy to see why Herbert has earned more praise than his Miami counterpart. He had a phenomenal season, throwing 31 touchdowns. That was enough to break the rookie record set by Baker Mayfield during the 2018 season. On top of that, his 4,336 yards nearly set another rookie record, and he threw just ten interceptions.
On the other hand, Tua threw for a far more pedestrian 1,814 yards, 11 touchdowns, and five interceptions. Of course, as Tua fans will rightly point out, this comparison is not fair to him. Herbert started all but one game for Los Angeles this season. Meanwhile, Tua only started nine and didn’t finish two of them. As a result, he threw 305 fewer passes than Herbert.
With those limitations, it would be ludicrous to expect Tua to match Herbert’s statistics. He wasn’t given the same number of opportunities to succeed. Therefore, if we want to evaluate the two quarterbacks fairly, we need a different method.
Using the OVM to compare Herbert and Tua
In order to solve this problem, let’s turn to the Offensive Value Metric (OVM), which was created by the (Bx) Movement in part for situations like this one. It grades players based on how much impact they had on their own statistics. As such, it allows us to examine them in a way that isn’t restricted by their playing time or the weapons surrounding them.
Despite their wildly different seasons, Justin Herbert and Tua Tagovailoa had virtually identical OVM grades. Taking the entire year into account, Herbert earned a grade of 23.9, while Tua lagged slightly behind at 23.55. The difference being so minor indicates that, despite the wide gulf in their statistics, the two rookies provided a nearly identical amount of value to their offenses.
Additionally, it is worth noting that neither of those grades are particularly high. For context, both rank in the bottom half of all qualifying quarterbacks this season (although that does include players with wildly different sample sizes). More notably, they rank well below fellow rookie Joe Burrow. His grade of 28.69 ranked fifth among qualifying NFL quarterbacks at the end of the regular season.
In short, Herbert and Tua had almost exactly the same level of impact on their offense’s passing production, and that they fared poorly in that regard when compared to the rest of the NFL.
Explaining the advanced metrics behind the two quarterbacks OVM grades
Given how close Justin Herbert and Tua Tagovailoa’s OVM grades were, it likely won’t come as much of a surprise that they also had similar advanced metrics. Only slight differences set them apart from each other. However, the areas of strength for each quarterback conflict with the conventional narrative.
The chart below shows how the two quarterbacks performed on several of the most important statistics involved in calculating a quarterback’s OVM grade. Their intended air yards (IAY), their intended air yards exclusively on completions (CAY), how often they threw into tight windows (aggressiveness), their completion percentage, and their expected completion percentage according to the NFL’s calculations are all factored in.
| IAY | CAY | Agg. | Comp.% | eComp.% | |
| Herbert | 7.5 | 5.2 | 18% | 66.6% | 65.1% |
| Tua | 7.7 | 5.3 | 20.3% | 64.1% | 65.5% |
Although some have portrayed Tua as a game manager, he was actually more aggressive than Herbert across the entire season. He threw into tight coverage over two percent more often than Herbert did. Additionally, he threw the ball slightly further downfield on both his completions and incompletions.
Meanwhile, despite his inconsistencies in college, Herbert was actually the more efficient quarterback. His completion percentage was about two percent higher than Tua’s, despite his expected completion percentage being slightly lower.
It is important to remember, however, that these differences are exceedingly minute. They paint an interesting picture, but ultimately the two quarterbacks were nearly identical in most ways relating to their advanced metrics.
Both quarterback’s OVM grades varied dramatically throughout the season
As we have seen, the OVM graded Justin Herbert and Tua Tagovailoa similarly overall. However, looking at their weekly grades shows two distinctly different patterns. Below are a pair of charts displaying how the two quarterback’s grades from each week of the regular season, marked with black dots. The yellow lines mark the league average OVM grade for quarterbacks during the 2020 regular season.
Herbert got off to a strong start this season. However, as the season wore on, his grades began to vary dramatically. That made it difficult to predict how he would perform in a given week. Tua Tagovailoa was similarly inconsistent, but his grades shifted in a different way. His first start earned him his worst grade of the season. Then, he saw a dramatic improvement the next week before steadily declining for the remainder of the season.
In Herbert’s case, I’m inclined to chalk the variance up to the inconsistent play you often see from rookies, especially those like Herbert, who weren’t necessarily expected to be finished products coming out of college. Tua’s pattern is more interesting. His abysmal first start can likely be explained by inexperience, but his season-long decline is more worrying.
It is possible that defenses started to figure out how to defend Tua as the year went on. Or perhaps a conscious strategy change from former offensive coordinator Chan Gailey lessened Tua’s impact. Regardless of the exact reason, however, the Dolphins need him to reverse that trend next season.
Only time will tell where Justin Herbert and Tua Tagovailoa will end up
History has shown us that you can’t always trust a quarterback’s performance during their rookie season. That level of play often doesn’t carry over into the rest of their career. You might recall that Robert Griffin III, Sam Bradford, and Vince Young were all named Rookie of the Year. Unfortunately, none of them were able to live up to their early promise. On the other hand, Josh Allen had an abysmal rookie season but has had an MVP-caliber 2020.
It is still far too early to say which paths Herbert and Tua will follow. Twenty years from now, we might look back on this season and talk about how Herbert’s rookie season was simply a flash in the pan. Or maybe we’ll joke about how first-ballot Hall of Famer Tua Tagovailoa was benched for Ryan Fitzpatrick twice during his rookie season. For now, Herbert is earning more praise, and he deserves it. But don’t count Tua out just yet.
Lucas Ellinas is a writer for Pro Football Network. You can follow him on Twitter @Lucas_Ellinas.