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We don't need fancy numbers or historical comparisons to tell us the Dallas Cowboys' rookie quarterback-running back duo of Dak Prescott and Ezekiel Elliott is doing something special. Most of us have seen each player's impact with our own two eyes.

The NFC-leading Cowboys wouldn't be close to 7-1 without Prescott and Elliott. Prescott was the eighth quarterback selected in the 2016 draft, but he's the fourth-highest-rated passer in the NFL. Elliott, who was drafted fourth overall, leads the league in rushing by an 84-yard margin.

At midseason, they undoubtedly rank 1-2 in the Offensive Rookie of the Year race.

As Rick Gosselin of the Dallas Morning News recently wrote:

The Elliott-Prescott tandem is already the most productive set of offensive skill players the Cowboys have ever claimed in the same draft. The franchise appears set at those two key positions for at least the next six years, and Elliott and Prescott have the chance to become the greatest quarterback-running back tandem ever to arrive together in the same NFL draft.

But to get an even better feel for how much of an impact Prescott and Elliott have made as rookies, let's take a look back in time.

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Pro Football Reference has a nifty metric called approximate value (AV), which is "an attempt to put a single number on the seasonal value of a player at any position from any year." With that numerical value on any player's season, we can comb through past years in order to find seasons in which multiple rookies on the same team had strong AV totals.

Dating back to 1960, we found 14 teams that possessed two rookies with approximate values in the double digits. Here's a breakdown.

Top duos in modern and semi-modern NFL history, sorted by combined approximate value

2012 Washington Redskins: Robert Griffin III and Alfred Morris

Combined AV: 31

The first duo on the list provides our best comparison to Prescott and Elliott. A quarterback and a running back—one drafted in the top five, one drafted several rounds later.

In 2012, Griffin put together arguably the best rookie season for a quarterback in NFL history. His 102.4 passer rating remains the highest in NFL history among rookie signal-callers with at least 10 starts, and only Cam Newton had a higher rookie quarterback AV than his total of 18. Throw in a rookie quarterback record 815 rushing yards, and he was the runaway Offensive Rookie of the Year.

Washington's head coach, Mike Shanahan, told reporters that season:

I don't think anybody in the history of the league has played at his level. At least over the last 40 years, when I take a look at the numbers and what he has done, I don't think anybody has played at his level. As we've talked about before, he's got a unique skill set — his ability to throw, drop back, play action, put a threat on a defense with his running ability — and he will just get better and better. He's just scratching the surface.

Meanwhile, Morris rushed for 1,613 yards, which remains the third-highest rookie total in NFL history. He somehow fell short of the Pro Bowl, but he still had an AV of 13.

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"It's the same thing I've been saying every week; the first guy isn't bringing him down," Redskins fullback Darrel Young said at the time, according to Will Whitmore of the team's official website. "I don't know what else to say, he's just Alfred. He's still running guys over. He's just making plays. He's a tough runner, a humble guy, and you don't see that too often."

In terms of AV, Griffin and Morris were two of the 49 most valuable players in the NFL.

1965 Chicago Bears: Gale Sayers and Dick Butkus

Combined AV: 31

Sayers had a truly epic rookie season with 1,374 scrimmage yards, 20 touchdowns on offense and two touchdowns as a return man. He was a first-team All-Pro, his AV ranked second to only Jim Brown and he won the United Press International Rookie of the Year award (this was before the Associated Press started handing out awards for offensive and defensive players in 1967).

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With five interceptions and seven fumble recoveries, Butkus was also a first-team All-Pro with an AV of 13.

By that measure, Sayers and Butkus were two of the 32 most valuable players in the NFL.

"I don't think anybody was ever equal to Sayers in some of the things he did," former teammate Bob Wetoska told Alex Marvez of Fox Sports last year. "Butkus knows no equal."

1964 Washington Redskins: Charley Taylor and Paul Krause

Combined AV: 28



Taylor became a great receiver, but he won the UPI Rookie of the Year award as a running back. He tied for second in the league with 1,569 yards from scrimmage, and he had an approximate value of 15.

Krause joined Taylor in the Pro Bowl thanks to a league-leading 12 interceptions. He was also a first-team All-Pro with an approximate value of 13.

By that measure, Taylor and Krause were two of the 33 most valuable players in the NFL.

2012 Seattle Seahawks: Russell Wilson and Bobby Wagner

Combined AV: 26

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Neither Wilson nor Wagner won a Rookie of the Year award, and Wagner didn't make the Pro Bowl. But the third-round quarterback was the league's fourth-highest-rated passer, earning an AV of 16. And Wagner and Paul Posluszny were the only players in the league with at least three interceptions, two sacks and 85 tackles.

They both played massive roles on a team that was a Super Bowl contender.

Other notable duos

1981 New York Giants: Lawrence Taylor and Bill Neill

Combined AV: 27

Taylor is the only rookie to win the Defensive Player of the Year award, so his AV of 17 carries Neill, a fifth-round nose tackle who started all 16 games but failed to make the Pro Bowl and had an AV of just 10. Few viewed Taylor and Neill as a duo because one made a substantially larger impact than the other.

1973 Cincinnati Bengals: Boobie Clark and Isaac Curtis

Combined AV: 26

Offensive weapons Curtis and Clark had a combined 2,167 yards from scrimmage as part of a 10-4 Bengals team. Clark ranked seventh in the league with 1,335 yards from scrimmage and had an AV of 14, but the back failed to make the Pro Bowl. The more heavily hyped Curtis ranked fifth in the NFL in receiving yards, earning a rookie Pro Bowl nod. But his AV was only 12.

2002 Denver Broncos: Clinton Portis and Ben Hamilton

Combined AV: 25

Portis ranked fourth in the NFL with 1,508 rushing yards and posted an AV of 15, but he failed to make the Pro Bowl. Same with Hamilton, who started 16 games in the interior offensive line for a winning team but settled for an AV of 10.

1967 Detroit Lions: Lem Barney and Mel Farr

Combined AV: 23

In '67, the Lions had the AP Offensive Rookie of the Year (Farr) and Defensive Rookie of the Year (Barney). Farr ranked fifth in the league in rushing and earned a Pro Bowl nod with an AV of 10. Barney was also a Pro Bowler with a league-high 10 interceptions and three defensive touchdowns, earning an AV of 13.

1980 Atlanta Falcons: Buddy Curry and Al Richardson

Combined AV: 22

The linebackers split the Defensive Rookie of the Year award in '80. Richardson picked off seven passes and earned an AV of 12, while Curry recorded three interceptions and scored a defensive touchdown. They played critical roles as the Falcons won the NFC West with a 12-4 record. But neither made the Pro Bowl.

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2006 New Orleans Saints: Reggie Bush and Marques Colston

Combined AV: 22

Bush had 1,307 yards from scrimmage and played a key role as a returner, which was enough for an AV of 12 but didn't get him a Pro Bowl nod. Colston had a remarkable 1,038 yards and eight touchdowns as a rookie seventh-round pick, but he didn't make the Pro Bowl either and "settled" for an AV of 10.

2011 Cincinnati Bengals: Andy Dalton and A.J. Green

Combined AV: 21

Both Dalton and Green made the Pro Bowl as rookies in '11, as the second-round quarterback posted an 80.4 passer rating and the first-round wide receiver went over 1,000 yards with seven touchdowns. Still, neither had an especially high AV number for a 9-7 Bengals team.

1971 New England Patriots: Jim Plunkett and Randy Vataha

Combined AV: 21

They're listed because they both had double-digit AVs, but both barely qualified. Neither won a Rookie of the Year award, and neither made the Pro Bowl. Plunkett was the NFL's 11th-highest-rated passer, and Vataha ranked second in the league with nine receiving touchdowns, but neither could do much to save a Patriots team that had a losing record.

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1983 San Francisco 49ers: Roger Craig and Bubba Paris

Combined AV: 20

Craig had a solid 1,152 yards from scrimmage, while Paris started all 16 games at left tackle for a 10-6 49ers team. Neither made the Pro Bowl, though, and both barely qualified with AVs of 10.

2013 San Diego Chargers: Keenan Allen and D.J. Fluker

Combined AV: 20

Two non-Pro Bowlers with AVs of 10. Allen was great with 1,046 yards and eight touchdowns, while Fluker was solid in 15 starts at left and right tackle, but they're only listed because they both (barely) had double-digit AV totals.

Only one duo really compares

I haven't been holding you in suspense regarding the AV totals that belong to Prescott and Elliott at midseason. That's because they don't exist. Pro Football Reference uses a complex formula to calculate AV totals, which includes adjustments for All-Pro and Pro Bowl nods.

That said, I asked PFR if it could make an educated guess as to the pace both Prescott and Elliott are on in terms of AV. Its "rough and unofficial" estimation? Elliott at 12 or 13, and Prescott at 17.

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That seemingly conservative pace would put Prescott and Elliott ahead of Taylor and Krause and just back of the Sayers-Butkus and Griffin-Morris pairs.

But those first two duos didn't team up on the same side of the ball, and both predated the Super Bowl era. So if we're looking at offensive or defensive rookie duos in modern NFL history, the ultimate comparison should be between Prescott-Elliott and Griffin-Morris.

Here, outside of their AV totals and projections, is what the numbers say:

Comparing Prescott-Elliott 2016 to Griffin-Morris 2012 Category Prescott-Elliott* Griffin-Morris Record together 14-2 9-6 Completion percentage 66.5 65.6 Accuracy rate 74.7 79.6 Pass/rush TD per game 2.9 2.5 Interception rate (%) 0.8 1.3 Turnovers/game 0.6 0.6 Yards/pass attempt 8.1 8.1 Passer rating 104.2 102.4 QBR 82.8 75.6 QB yards/carry 4.0 6.8 QB rush yards/game 15.6 54.3 RB yards/carry 5.0 4.8 RB rush yards/game 111.4 100.8 RB scrimmage yards/game 130.8 105.6 QB rating under pressure 63.5 89.3 Accuracy rate on deep passes 45.0 50.0 Combined PFF grade 41.0 57.7 Combined approximate value 29.5 31 * Pace (Pro Football Reference/Pro Football Focus/NFL.com)

Working to the Dallas duo's advantage:

They're winning at a much higher clip than Griffin and Morris were.

They have higher mainstream rate-based numbers (touchdowns and yards per game, yards per rush, passer rating, QBR).

Working to the Washington duo's advantage:

Griffin was a much more effective rusher than Prescott.

Griffin has superior advanced numbers (passing deep, passing under pressure, Pro Football Focus grade).

It's clear based on pressure numbers and offensive line grades that Griffin and Morris had less support than Prescott and Elliott do.

Altogether, Griffin has a small edge over Prescott and Elliott has a small edge over Morris, which makes this close.

Of course, that's assuming Prescott and Elliott remain on track. Either could hit a rookie wall, but both have picked up steam as the season has worn on, which could indicate they'll blow past Griffin and Morris during the second half of the 2016 season.

Either way, we're witnessing history.

Brad Gagnon has covered the NFL for Bleacher Report since 2012.

Follow @Brad_Gagnon