We continue our “Packers 100” countdown with a rundown of the Packers’ top traits. Green Bay Packers football is just 59 days away. You can find the full countdown here.

For the next five days of the “Packers 100” countdown, I’ll be counting down the top five traits that the Packers have on their team. These will be physical abilities which are so far above the NFL baseline that they make these players some of the best in the league.

First, the two traits which just missed making my list: Eddie Lacy’s balance and Jeff Janis’ speed. Lacy’s balance is perhaps his biggest strength, as it allows him to maintain a center of gravity over his feet and fall forward where most other running backs could not. Janis has proven to be a special teams demon, but his speed has been mostly ineffective on offense.

For our No. 5 trait, we’ll look at the only player on the Packers team who can lay claim to being even faster than Janis: Sam Shields.

Sam Shields’ speed

When Shields was signed as an undrafted free agent before the beginning of the 2010 season, pretty much the only thing people cared about was his speed. His 40-yard dash was timed as low as 4.25 seconds at the Miami pro day, easily making him the fastest player on the roster.

In his rookie season, the Packers tried to harness his speed in the same way they’ve attempted to use Janis—kick returns. Shields was pretty mediocre in that job though, averaging just 21.5 yards per return.

The difference between Janis and Shields, at least so far, is that Shields has been able to use his blazing speed to become a reliable player. Since bursting onto the scene in the latter part of his rookie season, Shields has climbed his way up to the top of the depth chart due to the departures of Charles Woodson and Tramon Williams.

As a converted college wide receiver, Shields has never had impeccable technique. His technique has improved greatly due to the tutelage of Joe Whitt since coming into the league, but it’s still not near the level of a player like Richard Sherman (who infamously ran the 40-yard dash in 4.56 seconds.) He has unreliable hands, as witnessed in last year’s divisional playoffs, and he is more of a liability than an asset in run defense.

What Shields has, though, is speed that cannot be beaten by any receiver in the National Football League.

This speed has turned him into a top ten cover corner in the NFL, it has helped him earn and justify his four-year, $39 million contract, and it has made him one of the most indispensable players on this Packers roster.

Shields largely locked down Dez Bryant and Calvin Johnson in consecutive weeks last season, and the defense haemorrhaged yards in his absence. After spraining a shoulder at midseason, the team gave up nearly 1,000 yards in two losses to the Denver Broncos and Carolina Panthers. When Shields was concussed later in the season, Amari Cooper’s 4.42 speed proved to be too much for the Packers’ younger cornerbacks to handle.

So why is speed so important to Shields?

Speed is what allows Shields to be who he is as a cornerback. He doesn’t have the discipline or technique to frustrate top receivers all game with his positioning. But Shields’ speed allows him to take chances that other players can’t. He can peek into the backfield, allow huge cushions to receivers, and generally take riskier angles in coverage than would be advisable for most players. While this will sometimes result in big plays for the offense, his improved discipline has made him a largely reliable No. 1 corner.

His speed is crucial to the entire defense. When Shields is playing man coverage, Dom Capers can feel comfortable rolling Morgan Burnett down into the box to play in run support. There’s no need for the double high safety shells that invite teams to gash the Packers’ suspect run defense.

While his speed used to be a crutch to overcome poor technique, it has become an invaluable asset for one of the league’s very best cover corners.

It will be interesting to see how Shields’ career progresses in his later years. Will he be able to age as gracefully as fellow super-athlete Charles Woodson did? That may be up to his willingness to improve his abilities in run support and continue honing his discipline in coverage.

For now, though, speed is the defining characteristic of the elder statesman of the Packers corners.