Rick Osentoski/Associated Press

One of the earliest surprises of the NFL's free agency featured Green Bay Packers cornerback Sam Shields.

Shields, a former undrafted free agent out of Miami in 2010, signed a $39 million contract for four seasons. His $12.5 million signing bonus was a signal of trust from Packers general manger Ted Thompson in Shields' continued development.

Thompson has typically preferred to focus on retaining his franchise's own players and making quiet additions in free agency. Shields has a good reputation around the league, but few expected him to sign a deal so big.

Now, the question is whether Shields really deserves this deal or if Thompson became too attached to a player he had uncovered all those years ago. In order to answer this question, Shields is to undergo the Pre Snap Reads cornerback analysis.

Explaining the Process

Qualifying Plays

Plays that count:

Every snap that has the cornerback in man coverage no matter where the ball is thrown.

The above includes sacks, quarterback scrambles and plays where the defensive back has safety help.

Plays that don’t count:

Screen plays. Even if the receiver isn ’t part of the screen, these plays do not count.

’t part of the screen, these plays do not count. Plays where either the receiver or cornerback doesn ’t follow through his whole assignment.

’t follow through his whole assignment. Zone plays. Any ambiguity in this area will disqualify a play.

Any prevent coverage situations.

Receptions in the flat without a route run.

Running plays (duh!). Including designed quarterback runs.





Failed Coverages

The ball does not have to be thrown in the defensive back’s direction for the coverage to fail. This is NOT an analysis of how many completions the cornerback allowed, that can be found elsewhere. This is an analysis of how good his coverage is on any given play.

Failed coverages can come at any point of the route, but it is subjective to where the players are on the field in relation to the quarterback. Typically, defensive backs must be within arm's reach for underneath/intermediate routes. On deeper passes, there is greater leeway given to the defender.

Failed coverages can be subjective. They must be determined by the situation considering the length of the play and other such variables.

Shut Down

This category is reserved for those plays when receivers would have to make superhuman catches to beat the coverage. The best example of this is when receivers line up wide and try to run down the sideline, but the defensive back gradually guides them towards the sideline, suffocating the space they have to catch the football in. If a receiver is on the white sideline, he is shut down.

In Position

This is the opposite of a failed coverage. In order to be "in position," a defensive back has to be in a position to prevent a relatively well-thrown pass to his assignment.

Rick Osentoski/Associated Press

Individual Matchups

Individual matchups look exclusively at how Shields fared against specific receivers. Each receiver had to have at least four snaps in man coverage against the veteran cornerback. It doesn’t matter where or how Shields was beaten, this chart simply looks at if he was beaten or not.

No. Player Successful Snaps/Coverage Snaps Percentage 1. Terrance Williams 6/6 100.00% 2. Alshon Jeffery 5/6 83.00% 3. Patrick Edwards 7/9 78.00% 4. Cordarrelle Patterson 3/4 75.00% 5. Anquan Boldin 3/4 75.00% 6. Roddy White 3/4 75.00% 7. Josh Gordon 5/7 71.00% 8. Torrey Smith 6/9 67.00% 9. A.J. Green 6/10 60.00% 10. Antonio Brown 3/5 60.00% 11. Brandon Marshall 4/7 57.00% 12. Pierre Garcon 5/10 50.00% 13. Kyle Williams 2/4 50.00% 14. Josh Morgan 2/4 50.00% 15. Dez Bryant 4/9 44.00% 16. DeSean Jackson 3/7 43.00% 17. Calvin Johnson 2/11 18.00% Analytical Analysis through NFL.com

Paul Sancya/Associated Press

Weekly Breakdown

This section breaks down Shields' performances on a weekly basis, while also evaluating his specific strengths and weaknesses.

Week 1: San Francisco 49ers

Total Qualifying Plays: 11

Failed Coverages: 4

Shutdowns: 1

In Position: 6

Shields had a rough start to the season. That's not a massive surprise considering Colin Kaepernick lit up the Packers secondary in Week 1, but there were some very shocking traits that the 26-year-old cornerback showed off.

In man coverage, Shields showed off very poor footwork on more than one occasion.

NFl.com

In this example, he is fortunate that Kyle Williams is running a double move and not continuing in field after the initial break in his route. Shields badly overplayed the sideline here and gave Williams a clean inside break.

The one positive to take from this play is that Shields had the speed to recover after initially being beaten. He didn't get back into a perfect position, but he was able to legally slow down Williams and disrupt the play.

Shields made two egregious errors in zone coverage also.

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On the first, he does something that he did throughout the 2013 season. He keeps his eyes on the initial receiver too long and allows himself to be drawn too far forward. Shields has no awareness of Anquan Boldin breaking down the sideline to the area of the field where he needs to be.

A poor throw allows him to recover for the tackle but not to prevent the reception.

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For the final play, we got a look at Shields' poor technique, decision-making and his recovery speed. Again, he is let off by a bad throw from Kaepernick, but this really should have been an easy touchdown.

Week 2: Washington

Total Qualifying Plays: 22

Failed Coverages: 6

Shutdowns: 3

In Position: 13

Shields gave up a touchdown to Pierre Garcon in this game. It was a tough assignment for him because the offense lined up their receivers in a bunch tight to the formation. That trapped Shields to the inside for a split second while Garcon broke towards the pylon.

He was slow to react and he turned the wrong way on other occasions, but the most notable play of this game showed off his impressive ball skills.

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Shields has two obvious strengths. The first is his ability to recover when beaten early in plays—that was shown against the 49ers in Week 1. The second is his ability to locate and aggressively attack the football without making illegal contact against a receiver.

Week 3: Cincinnati Bengals

Total Qualifying Plays: 12

Failed Coverages: 4

Shutdowns: 1

In Position: 7

Save for two snaps, all of Shields' qualifying man coverage plays from this game came against A.J. Green. Green beat him with a crisp curl route, two deep comeback routes and a double move for a touchdown.

Shields started this game very well. He contained Green and Mohamed Sanu on a number of occasions before he came up with this interception.

NFL.com

The pass is late and inaccurate from Andy Dalton, but that shouldn't take away from Shields' excellent coverage. He would have been there to pressure Green on an accurately thrown pass, but once it was thrown inside, he was quick to react to it and showed good strength to take it from the receiver.

Importantly, two of Green's receptions against Shields came when Shields played decent coverage. The cornerback was simply too small to get to the football or affect Green as he made good catches with his hands.

This is an issue for Shields, because he is a small, light cornerback who can be consistently exposed in these types of situations.

Those situations didn't materialize as much as they should have in this game because Dalton badly overthrew a number of sideline routes intended for Green. That took away from the receiver's opportunities to expose Shields or Shields' opportunities to make up for the other occasions he was beaten.

Green left no doubt about who won for his touchdown reception.

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Shields consistently didn't handle double moves well. Even the more subtle fakes releasing at the line of scrimmage caused him all sorts of problems throughout the year. His footwork is very sloppy, and he allows his momentum to drag him forward too often.

Green exposed that on this play.

Week 5: Detroit Lions

Total Qualifying Plays: 15

Failed Coverages: 2

Shutdowns: 1

In Position: 12

With Calvin Johnson sidelined, Shields got to spend most of his day covering Patrick Edwards, Kevin Ogletree and Tony Scheffler. He gave up two coverages to Edwards, once when he turned the wrong way on an out route and once on a curl route when he couldn't reach a well-placed pass from Matthew Stafford.

Week 6: Baltimore Ravens

Total Qualifying Plays: 11

Failed Coverages: 5

Shutdowns: 0

In Position: 6

This was not a good performance for Shields.

He followed Torrey Smith around for the most part, but he was rarely left alone in single coverage with him. Shields showed off the speed to run with Torrey, which is a very impressive feat considering just how fast the Ravens receiver is.

However, his flawed footwork was on show again.

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On another double move, Shields gave up a defensive holding penalty because he bought too hard on the in route and couldn't adjust once Torrey turned to run towards the back pylon. Shields hadn't learned how to adjust his feet better and he didn't for the remainder of the season.

To worsen matters, Shields had two more egregious plays in zone coverage. One of which led to a touchdown for Jacoby Jones.

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From the beginning of the play, Shields is in trouble. He fixates too much on the quarterback and shows no awareness of Jones running past him. He never gains enough depth and is unable to recover by backpedalling.

Week 7: Cleveland Browns

Total Qualifying Plays: 11

Failed Coverages: 3

Shutdowns: 1

In Position: 7

This game featured Shields' most impressive play of the season so far.

NFL.com

This is the kind of play that has earned Shields a reputation as one of the more promising players in the league. He turns and runs with Gordon before locating the ball early and extending fully to nearly get the interception.

Shields simply doesn't do this often enough. In fact, it's very rare that he plays with such control and discipline.

Week 8: Minnesota Vikings

Total Qualifying Plays: 10

Failed Coverages: 2

Shutdowns: 0

In Position: 8

There was little to take from the Vikings game because the offense focused so much on running the ball, and the Packers played a lot of zone. It was at least a positive that Shields didn't have any major mistakes in zone or man coverage.

Week 9: Chicago Bears

Total Qualifying Plays: 11

Failed Coverages: 2

Shutdowns: 0

In Position: 9

New Tampa Bay Buccaneers quarterback Josh McCown saved Shields from giving up another touchdown to a double move.

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Brandon Marshall beats Shields, but the quarterback hesitates while looking at Marshall running free. Furthermore, because McCown doesn't have a strong arm, he has to loft the ball very high in the air. This gives Shields a chance to recover and even turn around to find the ball.

Shields plays the ball well, but he should never have had the opportunity to.

This was an aspect of Shields' game that was obvious, but another aspect was put on show in this game also. Shields is a very poor tackler. According to Pro Football Focus (subscription required), Shields missed nine tackles in 2013.

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The problem is, a large number of those tackles were plays you'd expect an average cornerback to make.

Not only is Shields slight and weak in the tackle, he has a very timid approach to running backs. He takes too many bad angles towards tight ends and receivers in space and is a liability in run defense as a whole.

Week 10: Philadelphia Eagles

Total Qualifying Plays: 9

Failed Coverages: 4

Shutdowns: 0

In Position: 5

DeSean Jackson exposed Shields' inability to stick with receivers through breaks on a number of occasions. One of those occasions was a double move...again.

Week 11: Injured

Week 12: Injured

Week 13: Detroit Lions

Total Qualifying Plays: 12

Failed Coverages: 10

Shutdowns: 0

In Position: 2

No cornerback goes into a game expecting to shut down Calvin Johnson. In previous analyses, cornerbacks have done well against Johnson without ever shutting him down.

The best cornerbacks can stick with Johnson, something that is an achievement by itself because he is unnaturally fluid for a receiver of his size, but very few have the ability to match his size and strength at the catch point.

Shields is a terrible matchup for Johnson because of their relative sizes, but critically Johnson didn't use his size to destroy Shields in this matchup.

Early on, Johnson ran two slant routes when he turned Shields the wrong way around with his release. Shields overplayed the sideline route badly. Two successful curl routes showed off how Shields floats at the top of routes, before Shields fell down on a comeback route.

A double move should have given Johnson a touchdown, but he dropped it. Another drop came soon after on a wide-open slant route against Shields before Kris Durham beat him on his sole snap with a good crossing route.

Shields had an interception in this game. It was an impressive play when he high-pointed the ball against Johnson after initially playing zone coverage. However, that play badly manipulated the perception of the actual performance.

Shields was roasted in an area where he was supposed to be able to at least compete.

Week 14: Atlanta Falcons

Total Qualifying Plays: 9

Failed Coverages: 2

Shutdowns: 0

In Position: 7

Save for one release from Drew Davis that sent Shields in the wrong direction, he had a solid outing against mostly subpar receivers.

Week 15: Dallas Cowboys

Total Qualifying Plays: 21

Failed Coverages: 5

Shutdowns: 3

In Position: 13

It's incredible how often Shields' mistakes weren't punished by the offense. Dez Bryant had one massive play down the sideline after a double move, but a poor throw from Tony Romo cost Bryant a chance at running it all the way to the end zone.

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On that (in)famous interception where Shields showed off outstanding ball skills, the cornerback actually turned the wrong way and Miles Austin was left wide open.

Clay Matthews' presence underneath forced Romo to hold the ball. That gave Shields enough time to recover, and another poor throw from Romo gave him the opportunity to make another exceptional play on the ball.

This play somewhat summarizes Shields as a player. He will be beaten often, and he's been very lucky to get away with these plays, but part of that is his ability to recover and play the ball.

Week 16: Pittsburgh Steelers

Total Qualifying Plays: 8

Failed Coverages: 3

Shutdowns: 0

In Position: 5

Emmanuel Sanders scored a touchdown against Shields with a double move on an extended play.

Week 17: Chicago Bears

Total Qualifying Plays: 7

Failed Coverages: 2

Shutdowns: 1

In Position: 4

Although the Bears couldn't sustain drives, there was a lot to watch with Shields.

Marshall exposed his height on a sideline route before Shields caught an interception on a Hail Mary play. Arguably his best play of the season as a whole came when he ran with Alshon Jeffery down the sideline before punching the ball out of his hands at full extension.

It was the type of play that Shields did only a handful of times all season long and something he needed to do a lot more of if he wanted to be considered a top-quality cornerback.

Wildcard Round: Injured on Second Snap of Game

2013 NFL Season Total:

Total qualifying plays: 169

Failed coverages: 54

Shutdowns: 11

In Position: 104

Success rate for the season: 68 percent

In Comparison to Alterraun Verner:

Total qualifying plays: 169

Failed coverages: 34

Shutdowns: 31

In position: 104

Success rate for the season: 79.8 percent

Results at Spots

Qualifying plays at left cornerback: 54

Failed coverages at left cornerback: 25

Success rate at left cornerback: 46 percent

Qualifying plays at right cornerback: 108

Failed coverages at right cornerback: 26

Success rate at right cornerback: 76 percent

Qualifying plays in the slot: 7

Failed coverages in the slot: 3

Success rate in the slot: 57 percent

Results versus Routes

(Percentage is Success Rate)

1. Post 100%

2. Sideline 95%

3. Seam 80%

4. Curl 74%

5. Out 72%

6. Comeback 69%

7. Crossing 64%

8. Slant 50%

9. In 33%

10. Double Move 27%

Sam Shields has excellent speed and good ball skills. Those are good traits to have as a cornerback, but alone they don't make you a good player.

It's easy to build a reputation on those two traits, because they stand out more than any other for most who watch cornerbacks. However, Shields is a great subject to show off the importance of footwork, awareness and good technique. He is severely lacking in each of those areas.

Shields was paid a huge amount of money for what he is expected to be over the coming seasons. Maybe he will be a star cornerback, but in 2013 he was barely a good starter. He has been given a very positive reputation for two reasons.

The first is that he is able to get his hands on the ball, something that always resonates well with onlookers. The second is that he plays on a defense that is full of holes elsewhere that take the spotlight away from his errors.