The Miami Dolphins haven’t had an elite quarterback since Dan Marino retired. So the Dolphins trading a late second-round pick for Josh Rosen has resulted in a lot of excitement.

Josh Rosen was a top ten pick in last year’s draft. And he still has a lot of potential, despite playing poorly during the previous season. However, most people believe that Rosen has just one year to show that he can be the future for the Miami Dolphins. Next year’s crop of quarterbacks, led by Tua Tagovailoa, are very talented, and Rosen needs to play well for the Dolphins to pass on those players. But exactly how well he needs to play is less obvious. In theory, though, we should be able to find a statistical threshold that, if Rosen were to meet it, he would be guaranteed the starting job for the foreseeable future.

First, Rosen needs to win the starting job over Ryan Fitzpatrick. Assuming he does, Rosen will likely only have the 2019 season to prove himself for the long-term. As a disclaimer, I would like to make clear that statistics cannot definitively show whether or not Rosen deserves more time as the Dolphins starting quarterback.

Many factors go into determining whether or not a player is successful, and not all of these are reflected in their statistics. Rosen himself is an excellent example of this. While he certainly did not play well last season, the Arizona Cardinals’ offense had many problems that were not in his control. And the problem can happen in reverse as well. A quarterback with a great coach on an incredibly talented team might look better statistically than he actually is. In short, while I believe that statistics are valuable tools, a full evaluation of Rosen will also need to take how he looked on the field into account.

How much does Josh Rosen need to improve by?

Other than the talent in next year’s draft, the primary reason Rosen is on such a short leash is simply that he didn’t play particularly well last season. As a rookie, Rosen threw for just 2,278 yards, 11 touchdowns, and 14 interceptions. He also had one of the worst PFN Offensive Share Metric (OSM) grades of any quarterback at 20.91. To be fair to Rosen, he did play on the worst offense in the NFL. So his performance was not entirely his fault. In spite of this, some fans and media members do not believe Rosen will improve. For him to prove them wrong, he will need to elevate his play by a significant amount.

Opinions on exactly how much Rosen will need to improve will vary from person to person. That said, there are clearly extremes on both ends of the statistical spectrum that would determine whether or not Miami should draft a quarterback in 2020. For example, if Rosen throws more than 5,000 yards and 50 touchdowns, as Patrick Mahomes did during his sophomore season, then I would assume that most Dolphins fans would be in favor of keeping him around, regardless of how he got to those numbers.

On the other hand, if Rosen plays just as poorly as he did last year, which he really shouldn’t considering it would be hard to be in a worse situation for a quarterback than he was with the Cardinals, then I think the Dolphins can safely move on. Again, these are the extreme scenarios, but you see my point. The question then, is this: where is the breaking point? What level of statistical improvement would show Miami’s coaching staff that Rosen is their franchise quarterback?

Matching Baker Mayfield’s statistics

I believe that a reasonable place to start would be with one of the quarterbacks drafted before Rosen in 2018: Baker Mayfield. Mayfield had a phenomenal rookie season and nearly led the long-suffering Cleveland Browns to the playoffs. After becoming the starter, Mayfield threw for 3,725 yards, 27 touchdowns, and 14 interceptions. Going into 2019, most people firmly believe that the Browns have finally found their franchise quarterback. So, if Rosen performs at the same level, then it only makes sense to view him in a similar light, even if it took him a year longer to get there.

If Rosen matches Mayfield’s 2018 statistics, then he will have increased his passing yards by more than 1,500 and thrown 16 more touchdowns, all while maintaining the same number of interceptions. That would be a dramatic improvement, one that would warrant further investigation. Of course, the 2018 Browns were significantly more talented than the 2019 Dolphins will be, particularly on the offensive line. Additionally, neither Rosen nor Mayfield played the entire 2018 season, so their numbers are slightly misleading. As such, expecting Rosen to replicate Mayfield’s numbers might be unrealistic.

What statistical benchmark does Rosen need to reach?

It would probably be more reasonable to compare Rosen to someone like Mitchell Trubisky, who threw for a modest 3,223 yards, 24 touchdowns, and 12 interceptions. However, that stat line is probably not enough to win Rosen the job on its own. Trubisky’s numbers have not been good enough to keep many fans of the Chicago Bears happy. And this is despite their team reaching the playoffs last season. And since Rosen is on a shorter leash than Trubisky, he would need to show his worth in other ways.

But regardless of who you are comparing Rosen to, these are the kinds of numbers that I believe you are looking for if you want to be confident in Rosen’s abilities. Approximately 3,500 yards, around 25 touchdowns, and a 2:1 touchdown to interception ratio. These aren’t necessarily elite statistics for a quarterback, but they aren’t that far off either. And this early into Rosen’s career, I think that kind of production is precisely what you are looking for. Therefore, if Rosen reaches or surpasses this benchmark, then I believe Miami should consider not drafting a quarterback in 2019.

Why Josh Rosen won’t become another Ryan Tannehill

I recognize that this will be a controversial opinion for some. Ryan Tannehill produced similar numbers to these on a couple of occasions during his time with the Dolphins. And some are concerned that Rosen will just be a continuation of the Tannehill experiment. But I have a few counterpoints to that. First, the first time Tannehill produced at that level was in 2014, when he was already 25. On the other hand, Rosen is just 22. And if he shows that level of promise in his second season, it says a lot about how much room he still has to grow.

Second, Tannehill’s career has become derailed by injury in recent seasons. He was actually looking quite promising before tearing his ACL in 2016. Unfortunately, this injury set in motion a chain of further injuries that would eventually end his career in Miami. And although Rosen has had injuries in the past, I don’t think there is any significant reason to believe that the same thing would happen to him. Taking these factors into account, while it is possible that Rosen will stagnate in the same way Tannehill did, I do not believe that such a scenario is particularly likely.

Josh Rosen’s future in Miami

Whether or not Rosen will succeed in Miami is still unknown. And what exactly that success would entail is very much up for debate. While I have made my own opinion clear, I think many will have higher standards for Rosen. Additionally, there is a lot more to a player than what appears on their stat sheet. A full evaluation of Rosen will need to wait until the 2019 season is completed. However, if he can reach the level of statistical success that I have suggested here, then he will have made an excellent case for being Miami’s starting quarterback for at least another season. And from there, maybe he can finally be the franchise quarterback the Dolphins have been waiting for.