GREEN BAY, Wis. -- There’s a reason the 40-yard dash is one of the most anticipated and important tests at the NFL scouting combine every year.

You can’t teach speed.

And when a player -- or worse yet, a team -- doesn’t have it, it’s obvious.

In the Green Bay Packers’ case, a lack of speed is perhaps the biggest contributor to their offensive woes.

It’s not a stretch to say the Packers have the slowest team in the league when it comes to the skill positions in the passing game.

A study of all 32 teams' top three receivers and No. 1 tight end at this point in the season confirmed that. Using 40 times of every player from their NFL combine test or, if they didn’t run at the combine, their college pro day, the Packers currently have the slowest foursome of top receiving targets in the NFL (see accompanying chart).

The combined average 40 time of receivers Randall Cobb (4.55), Davante Adams (4.56), James Jones (4.6) plus tight end Richard Rodgers (4.87) ranks as a league-worst 4.65 seconds. And at age 31, Jones probably couldn’t match his original time.

Even if you throw out the lumbering Rodgers and the tight ends, the Packers are on the slow end, tied for 26th among all teams’ current top three receivers, with an average 40 of 4.57 seconds.

Coach Mike McCarthy, playcaller Tom Clements and offensive coordinator Edgar Bennett can scheme all they want, but the biggest reason their receivers haven’t been able to get open enough has been a shortage of speed, according to one NFL scout.

Sure, precise route running can help receivers get open, but there’s no substitute for speed.

“You have to really do a little bit of both,” Bennett said. “Timing, rhythm, footwork -- all of that plays into our system, and I think our guys have to be in tune with that. I think they understand that from a fundamental standpoint, where they’re supposed to be from a depth standpoint. And overall communication, you have to be able to read the coverage and make the proper adjustments at the right times.”

A closer look at the Packers’ first offensive series in Sunday’s loss to the Panthers shows why speed matters.

On first down, Rodgers caught a short pass and because he couldn’t accelerate past Roman Harper, a 32-year-old safety who is 10 years removed from his 4.5-second 40-yard dash time, he managed just a 2-yard gain.

On third-and-9 after Eddie Lacy was stuffed for a 1-yard loss, the Packers went to their preferred offensive package with three receivers -- Adams and Jones outside with Cobb in the slot -- plus Rodgers and Lacy. Lacy stayed in to help protect against a six-man pass rush, leaving all three receivers and Rodgers single covered with a safety playing deep.

Adams, wide to the right, couldn’t beat Harper on an out-and-up route. Jones, split left, failed to outrun cornerback Josh Norman on a deep post. From the slot left and right, respectively, Cobb ran a crossing route against nickel cornerback Bene Benwikere and Rodgers ran up the seam against cornerback Charles Tillman. Neither was open.

Aaron Rodgers danced in the pocket, moving around for nearly 6.5 seconds, before Panthers defensive tackle Star Lotulelei sacked him.

The loss of the long-striding Jordy Nelson (to a preseason knee injury) and his 4.51 40 has slowed the offense.

“I mean, just run your route and win your route,” Jones said. “You know the technique that you’ve been coached to do to win your route. It doesn’t matter how fast you are or how slow you are or how quick you are. Everybody in that room has made plays. Everybody in that room knows how to run routes and get open.

“It’s just about making plays and like I said, we did it late. The defense had us on our heels in the beginning and we had them on their heels late in the game. We’ve just got to get back to what we do, move at a fast pace, run the ball, throw the ball.”

The Packers have more speed in their receiving corps with second-year pro Jeff Janis (4.42) and rookie Ty Montgomery (4.55), but neither is among the top three receivers at the moment. Janis hasn’t been able to earn consistent playing time and Montgomery has missed the past two games because of an ankle injury.

In an effort to jump-start the offense in the early stages against Carolina, McCarthy went back to an old tactic he used to employ in his early days as a head coach. Instead of playing no-huddle with the same personnel, he subbed on almost every snap in an effort to create mismatches. It didn’t work, and McCarthy went back to his standard three receivers, one tight end and one back and played no-huddle in the second half.

“That component has really never left our offense,” McCarthy said. “It’s just really where you tilt more, and I’m always going to tilt toward Aaron Rodgers with the ball. Based on the way we call the offense and the options that are given, I mean the guy under center has a lot better view than the playcaller from the sideline.”