Greg Cosell's draft analysis: Josh Rosen is the most refined, and perhaps best, QB in this class

Jared Goff was the first pick of the NFL draft two seasons ago, and had a very good 2017 season with the Los Angeles Rams. After watching two seasons of tape on UCLA quarterback Josh Rosen, I think Rosen is a better prospect than Goff was coming out of Cal.

If I had to choose, I’d probably pick Rosen as my No. 1 quarterback in this year’s class.

Rosen profiles as a pocket passer in the NFL, a Goff- or Matt Ryan-type quarterback. He still has enough mobility to make needed second-reaction plays, but he’s a high-level prospect because of his work from the pocket.

Rosen has very good mechanics that he repeated consistently: good ball position, firm base, excellent balance, compact delivery, good velocity. There was a calmness and poise to his pocket play. For NFL teams that value pocket play, Rosen will be a desirable prospect in this draft. He doesn’t have many weaknesses, as we’ll see as we break down his game.

Rosen has many high-level traits, especially from the pocket

Here’s a play that shows Rosen at his best. It is a play-action pass against UNLV in 2016, and Rosen’s initial read is to the boundary (short side of the field). He then goes back to the middle seam to beat the single-high safety who had rotated to the boundary. You see a firm touch throw with precise accuracy.

This field-level angle gives a good perspective on how he quickly came off his initial read when the defense took it away, and ended up hitting his secondary read for a score. Quickly eliminating what’s not there is a crucial skill for an NFL quarterback.

That is an advanced play for a college quarterback. He turned his back to the defense for the play-action fake and was able to snap his head around and instantly read the defense, which is a learned trait and a tough one to master. He quickly diagnosed what the defense had taken away from him. Then he beat the single-high safety with his secondary read, after the safety had rotated. And the throw was very well placed.

Rosen has a lot of refined skills even before he enters the NFL, and part of that is him playing in a UCLA pass offense that featured many NFL concepts. Rosen has a good understanding of the concepts he’ll be taught in the pros, and he also has extensive experience playing under center, which is not the case with many quarterbacks coming out of college.

One trait that will transition very well to the NFL is Rosen’s highly developed sense of timing and rhythm, with a good feel for progressions. On this 32-yard completion last season against Arizona, you see that Rosen stays calm in the pocket, works through his progressions and hits a secondary read with timing and rhythm. This is what NFL teams want from their quarterback in the pocket.

While Rosen is at his best in the pocket, he also has the capability of throwing on the move. A couple of touchdown passes against Arizona in 2016 illustrate that. On this one, he throws a precise pass after escaping the pocket, which led to a 62-yard touchdown.

Later in the game, Rosen made a big-time throw on a 29-yard touchdown. Rosen climbed the pocket with his eyes downfield and with bodies all around him, he threw an off-balance pass right as he was hit for a touchdown. This is an impressive play.

There’s a lot to like about Rosen. He has excellent delivery balance. He has good field vision with excellent awareness of route concepts against specific coverages, which is a product of the pro concepts he was taught at UCLA. Rosen has a refined sense of anticipation and can consistently deliver the ball with accuracy.

It’s easy to see why he can be a very good starting quarterback in the NFL.

There aren’t many clear weaknesses to Rosen’s game

I like to go through a prospect’s strengths and weaknesses, but my list of weaknesses for Rosen is pretty short.

Once in a while Rosen’s ball placement isn’t quite as precise as it needs to be. Those occasional lapses of accuracy need to be cleaned up, because Rosen’s game is built on precision pocket passing. He can’t miss routine throws because of his profile as a pocket passer.

There were times Rosen would leave deep balls short, and overall he’s not a drive thrower so there are some questions about his velocity when it’s demanded. There were also some interceptions in which he was too reckless.

While these are issues he’ll need to improve upon, it’s mostly nit-picking. When you watch Rosen’s tape, you don’t find many huge flaws.

How will Rosen transition to the NFL?

To succeed as a quarterback in the NFL over the long term, you need to be successful from the pocket. Rosen has a lot of tools needed to play from the pocket, such as a decisiveness playing within the structure of the offense, but also enough mobility to make second-reaction plays. While he might not have high-level arm strength, he has a good arm and he consistently succeeded with timing, anticipation and accuracy. That almost always transitions well to the NFL.

You get a sense of Rosen’s refinement as a prospect in many ways. Each quarterback near the top of this year’s draft has strengths, and are all high-level prospects in their own ways. But it wouldn’t surprise me if Rosen ends up being the best of the group. There aren’t many knocks on him coming into the NFL.

GREG COSELL’S PREVIOUS DRAFT BREAKDOWNS

Saquon Barkley is a great prospect, but not without some faults

Lamar Jackson can execute an NFL passing game

Josh Allen, a young wild stallion who needs to be channeled

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NFL analyst and NFL Films senior producer Greg Cosell watches as much NFL game film as anyone. Before the NFL draft, Cosell will join Yahoo Sports to share his observations on some of the top prospects.

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