The latest installment in the 49ers opponent quarterbacks series looks at NFC West rival Josh Rosen of the Arizona Cardinals.

Cardinals quarterback Josh Rosen was the fourth of five quarterbacks taken in the first round of the 2018 NFL draft at pick #10. Baker Mayfield (#1 to Cleveland), Sam Darnold (#3 to the New York Jets), and Josh Allen (#7 to Buffalo), were all drafted before him, and all made their starting debuts prior to Week Four. Josh Rosen got his first start last weekend, and to little fanfare. Only Lamar Jackson (#32 to Baltimore) has yet to start a game.

The tenth overall pick out of UCLA, however, may end up being the best of the bunch by the season's end if his first start is any indication, though I suspect few will notice due to how bad the Cardinals have been since the season started. If the Cardinals have any chance to win games, it will be because Rosen does all the right things when asked.

On a team like the Cardinals though, it shouldn't be expected that he'll perform to a high level week after week, after all, this is the NFL and rookie quarterbacks rarely sustain high levels of performance consistently. Recent quarterbacks Carson Wentz and Jared Goff went from poor rookie outings in 2016 to leading two top contenders for the Super Bowl. Deshaun Watson's season ended last year with a torn ACL in practice. Patrick Mahomes didn't become the full time starter until this season.

Aside from Mayfield, who has played phenomenal in his first game and a half so far, the rest of this year's class has been underwhelming thus far. Darnold hasn't been spectacular, neither has Allen, and the Ravens still can't figure out what they're doing with Lamar Jackson, even though Joe Flacco has been less than average in recent years.

With Rosen, the Cardinals entered 2018 offseason minicamps and OTAs with two veteran quarterbacks and the rookie. Sam Bradford was brought in on a one-year deal worth around $20 million and the Cardinals at the same time signed quarterback Mike Glennon to a two-year deal. It was understood that Bradford would enter the year as the starter.

Through the first three games, the Cardinals offense was stagnant facing the number 12- (Washington), number nine- (LA Rams), and number one- (Chicago) ranked defenses per Football Outsiders DVOA. However, that gave the Cardinals the excuse of starting the rookie in place of Bradford heading into Week Four against the sixth-ranked defense per DVOA, the Seattle Seahawks.

Rosen's stat line by itself was decent for a rookie starting his first game but suggests he didn't do much. He certainly didn't garner any national attention from it. On paper, the stat line does not do him any favors. When put into context with the film though, his receivers didn't do him any favors as well and are largely to blame for the relative lack of success.

The Cardinals receivers had four dropped passes for a total of at least 100 yards lost, two of which would've been for touchdowns, and one that could've possibly been a touchdown though it wasn't in the end zone. Had even one, or all three, of those been caught, then we might be talking about Rosen's impressive performance.

Instead, the Cardinals lost by three points to Seattle on a late field goal after Rosen set up the offense for the game winner late in the fourth, only to have it missed. Rosen finished the day 15 of 27, 55% completion, 180 yards, one touchdown, and no interceptions. Let's look at his first official performance and where he excelled.

DROPPED PASSES


The most significant factor affecting Rosen's potentially big day were the dropped passes as they very likely were the main reason the Cardinals did not win a close game. Two of those drops came from Larry Fitzgerald. Christian Kirk, J.J. Nelson, Ricky Seals-Jones added two more drops (Nelson's doesn't get counted as a drop due to a Seattle penalty negating the play, but only because it was dropped).



The first drop came on Rosen's very first series as the official starter. It's second-and-10 inside Cardinals territory. Rosen goes under center and executes a hard play fake with max protection, ensuring he can buy enough time in the pocket to get off a throw. The Seahawks send a fire zone blitz to Rosen's left with the defensive end to his right dropping into coverage.

The play fake draws the linebacker up so far that he has to turn and run to find Fitzgerald on the crossing route over the middle when he sees Rosen turn to throw. As the left side of the offensive line crumbles under the blitz, the tight end lunges to cut the blitzing linebacker but fails miserably and he hits Rosen just fraction of a second after he throws the pass.

The pass should've been slightly more behind Fitzgerald due to the leverage the defenders had on the throw but Fitzgerald wasn't in any real danger of a big hit and Rosen still fit the pass into a tight window over two defenders and in front of the safety. Fitzgerald can't haul it in.



Fitzgerald's second drop came at the start of the second quarter with the Cardinals threatening on the Seattle 11. Out of a gun far doubles formation, the Cardinals are running a mirrored curl/seam concept where the slot receivers run inside go-routes down the seam. Fitzgerald is working the seam from the left slot.

Rosen takes the snap and looks down the middle of the defense to hold safety Earl Thomas before coming back to Fitzgerald, who was working the seam against cornerback Justin Coleman (no. 28). Fitzgerald gets inside Coleman as Rosen comes back to his route and throws the ball.

Rosen puts it away from the outstretched hand of Coleman into extremely tight goal line coverage where rhythm and timing are arguably more important. A split second early or late and the pass is a missed opportunity for a touchdown. Instead, Rosen throws on time and with precision accuracy into the hands of Fitzgerald but he cannot bring in the pass. A catch is likely a touchdown in this scenario.

Two drops for Fitzgerald in this game alone is uncharacteristic, whereas he had four drops on 153 targets last season according to Pro Football Focus.



Rosen didn't suffer just short drops either. He was deadly accurate throwing deep as well, and two more went for deep drops. Cardinals receiver Christian Kirk is running a deep crossing route. As Rosen executes a play fake, the defense jumps up and Kirk runs right by his defender, who somewhat recovers.

Rosen leads Kirk up field toward the sideline and away from the defender in trail. Rosen steps into throw and gets hit just after he releases the pass, showing again that he is prioritizing his mechanics and accuracy over getting hit and throwing early, something you want to see from a rookie quarterback.

Rosen's pass goes right through Kirk's arms in stride, Kirk falls, and the pass is scored as incomplete. If he were to catch it, he likely scores or at least gets a big gain out of the throw.



Per Pro Football Focus, J.J. Nelson dropped seven passes on 54 targets last season, one of the worst drop rates for a receiver last season. There's no reason to expect that to improve this year. This drop came in the second quarter and likely would've been a touchdown. The play would eventually not count as a result of a hands to the face penalty by Seattle but had Nelson caught it and scored, that wouldn't have mattered.

Rosen goes under center and executes a hard play fake while the play call sends just two receivers downfield on a scissors concept where the receivers cross deep on a post from the outside and a corner route from the slot.

Nelson gets a free release from the outside and runs right by safety Earl Thomas, who got caught looking inside at the slot receiver giving an inside move before cutting out on a corner route. By that time, Nelson was in full stride running away from Thomas, who had to come out of his backpedal to turn and run.

Rosen drops backs under max protection, stays patient and allows the routes to develop downfield. He sees Nelson break free and launches a pass that Nelson is able to run under. However, as Nelson is going to the ground, he cannot secure it and it falls as just another incomplete pass.



Ricky Seals-Jones rounded out the drops with a drop down the left sideline in the flat where he could've picked up a first down on a crucial drive.

ACCURACY


Despite the dropped passes, Rosen regularly hit receivers in the intermediate to deep ranges with accurate passes in tight coverage.



The Cardinals put Rosen under center for play action seven times in this game and went to max protect while running just two routes downfield. On Rosen's only touchdown pass, they ran deep crossing routes that seemed to confuse the Seahawks secondary long enough for a receiver to get open.

Utilizing play action and max protect again here, Rosen finds Chad Williams in the back of the end zone after the corner and safety Earl Thomas end up in the same zone. Thomas recovers enough to trail Williams but Rosen's pass is low and away due to the defender's leverage and also the sinking corner underneath from the left sideline.

Rosen places the ball in a spot where Williams doesn't have to make a difficult adjustment because he's already moving in the direction of the throw. He just has to go down and get it. The low pass also saves him from a big hit from the two defenders in the zone. The play shows that Rosen understands defender leverage and where to place the ball.





On two separate throws in the fourth quarter, Rosen was somehow able to connect with his receivers in tight coverage despite also having two receivers run routes into the same area.

On both of these throws, Rosen doesn't panic when he sees this and instead shows great poise and decision making in hitting the right read in tight coverage. A lesser quarterback might have thrown it away.

Not Rosen. On both plays he holds the safety with his eyes long enough to find a window to throw to and delivers accurate passes in spots only the receiver can catch it.

Both throws have enough velocity and trajectory to get over the defender in coverage and yet still have precise timing to get there. Both throws also show how well Rosen can throw players open away from the coverage because of how well he understands defender leverage.

COVERAGE MANIPULATION


Usually the best way to get a quarterback off his spot is to send pressure. Against rookie quarterbacks, most teams will instead drop into coverage and try to confuse or bait a young quarterback into a mistake.



On this play, on an obvious passing down on third-and-11, the Seahawks drop seven into coverage and only rush four. The longer a young quarterback has to hold the ball, the more indecisive he becomes.

Instead, Rosen uses the coverage to his advantage. The tight end Seals-Jones runs a deep curl over the middle to the line to gain and Rosen's eyes and posture are locked into his route initially. The defense has him bracketed by the linebacker and safety and thinks it has baited him.

Rosen gives a quick pump fake that freezes the linebacker and safety over Seals-Jones and quickly comes back to Fitzgerald in the throwing lane he created for himself by selling the route to Seals-Jones. He hits Fitzgerald down the seam on a deep curl route for a gain of 16 yards.



On the Cardinals' last drive here on this play, they are tied 17-17 and are facing second-and-8 on a potential game-winning drive. Rosen drops back and shifts to his first read right away, Fitzgerald running an intermediate crossing route. He sees the safety sitting back deep to the far wide side of the field and that Fitzgerald is covered underneath.

He shifts quickly to his second read but the receiver is bracketed by the safety who rotated down or "buzzed" to a hook zone from his cover 2 pre-snap shell. Rosen has nowhere to go and immediately shifts back to the far flat and finds Kirk all alone.

Rosen delivers an accurate pass as he gets hit and the pocket collapses. Kirk picks up seven on second down, setting a up manageable third-and-1 that running back David Johnson picked up on the next play. Three plays later, kicker Phil Dawson missed a 45-yard field goal to give them the lead. On the ensuing drive, the Seahawks kicked the game winning field goal.

WHAT HE NEEDS TO IMRPOVE


Despite the fact that Rosen threw the ball generally well with great placement and accuracy and despite being able to manipulate coverages with his eyes, it should not be expected that he'll continue at such a high level of play week after week. To sustain this, though, and have any shot at continuing to be consistent, he'll need to work on his ball placement and decision making, two things he struggled with in the preseason.



On this throw from the preseason, Rosen just misses hitting his receiver down the seam for a big gain because the pass was inside. A closer look at his mechanics reveals that the plant foot was pointed down the middle of the field, causing Rosen to have to control the pass outside the numbers with his arm rather than his hips.



Rosen also showed that he can struggle with reading coverages. On this play, Rosen diagnoses the wrong read and doesn't notice the nickel defender dropping into the flat. He also hurries the throw, and it almost goes for a pick six.

These aren't problematic, though, since I think these are the exceptions to the rule right now based on how he played against the Seahawks. But it's easy to understand how they could become problems. Still, they should not become long-term issues. Rosen did more than enough to win the game on Sunday. Unfortunately, his supporting cast did not show up at critical times, in critical situations on critical drives. Cardinals fans are going to have to deal with the short-term pain of an inconsistent supporting cast on days when their rookie quarterback is less than stellar. Fortunately for them, Rosen's best days are ahead of him if the cast around him becomes consistent.

All pics and images courtesy of the NFL.

All statistics courtesy of Pro Football Reference.