Herd Hierarchy: Top 10 NFL free-agent signings of all time

NFL free-agency frenzy for 2021 is in full swing.

While every team hopes its new additions will pay off, "winning" in free agency isn't as easy as it seems.

However, sometimes a big swing, such as the New Orleans Saints' signing the now retired Drew Brees in 2006, can net big results — Super Bowl-level results.

That's why free agency is such a whirlwind but also a big-time gamble.

What are the most impactful free-agent signings in the history of the NFL? Colin Cowherd delved into the subject on "The Herd," breaking down his top 10 all-time signings. (Applicable contract information via Spotrac.com)

10. Patriots sign LB Mike Vrabel

Previous team: Pittsburgh Steelers

Initial contract details: Unavailable in 2001 with the New England Patriots

Cowherd's thoughts: "He was the perfect fit. They won three Super Bowls in four years. He became the glue guy and the IQ and the vocal leader. ... He's the greatest value free-agent ever."

9. Cardinals sign QB Kurt Warner

Previous team: New York Giants

Initial contract details: One year, $4 million in 2005 with the Arizona Cardinals

Cowherd's thoughts: "Total culture-changer. He made them a winner. They had not won their division since the mid-70s, and then Kurt Warner showed up for Arizona and changed everything. ... Arizona, from that point forward, we think of them as a competent franchise."

8. Packers sign DB Charles Woodson

Previous team: Oakland Raiders (now Las Vegas Raiders)

Initial contract details: Seven years, $52.7 million in 2006 with the Green Bay Packers

Cowherd's thoughts: "Green Bay was the only team that bid on him because ... he had not played a full season in the previous four with injuries. ... It was riskier at the time than you think."

7. Oilers sign QB Warren Moon

Previous team: Edmonton Eskimos (Canadian Football League)

Initial contract details: Five years, 4.5 million in 1984 with the Houston Oilers (now Tennessee Titans)

Cowherd's thoughts: "They became an offensive juggernaut with Warren Moon. He stabilized the franchise. They always had talent, but they never felt, like, put together right, and he ended all the chaos in Houston."

6. Ravens sign DB Rod Woodson

Previous team: San Francisco 49ers

Initial contract details: Three years, $5.7 million in 1998 with the Baltimore Ravens (via Front Office Football)

Cowherd's thoughts: "He really added an aggressiveness to the Ravens' defense, when they became a play-making defense. Some guys just get interceptions. Ed Reed [and] Rod Woodson become offensive players once they get those interceptions."

5. Cowboys sign CB Deion Sanders

Previous team: San Francisco 49ers 

Initial contract details: Seven years, $35.0 million in 1995 with the Dallas Cowboys

Cowherd's thoughts: "This is the flashiest free-agent signing of all time. It was the 'Deion Sweepstakes' ... It was the biggest, flashiest, most outspoken star to the biggest, flashiest brand."

4. Packers sign DE Reggie White

Previous team: Philadelphia Eagles

Initial contract details: Four years, $17 million in 1993 with the Packers (via Milwaukee Journal Sentinel)

Cowherd's thoughts: "It was the first offseason that featured free agency in the NFL, and he was the first big free agent to change teams. ... He was great. First big star to switch teams, and he completely, utterly delivered."

3. Buccaneers sign QB Tom Brady

Previous team: New England Patriots

Initial contract details: Two years, $50 million in 2020 with the Tampa Bay Buccaneers

Cowherd's thoughts: "Like Kurt Warner, he's a culture-changer. Now guys are taking pay cuts to stay with Tampa."

2. Broncos sign QB Peyton Manning

Previous team: Indianapolis Colts

Initial contract details: Five years, $96 million in 2012 with the Denver Broncos

Cowherd's thoughts: "They loved Tim Tebow, and [Broncos GM John] Elway was trapped. So he had to get a bigger star than Tebow to kind of save the franchise from what they viewed as a niche, college quarterback who had gotten on a hot streak in the NFL."

1. Saints sign QB Drew Brees

Previous team: San Diego Chargers (now Los Angeles Chargers)

Initial contract details: Six years, $60 million in 2006 with the Saints

Cowherd's thoughts: "End of story. Not only did he change the culture from a losing culture, he overcame [Hurricane] Katrina. He's been huge for the community. He was seemingly there forever. ... Greatest free-agent signing ... easily, of all time."

Check out Cowherd's full breakdown of "Herd Hierarchy" below: