The Iowa football program under head coach Kirk Ferentz has been sneaky good at getting players into the NFL. In Ferentz's 21 years at the head Hawkeye, 75 of his players have been drafted into the National Football League. But what might be even more impressive is the list of players who were NOT drafted that signed with teams and went on to earn millions. The Des Moines Register took a look at the highest earning undrafted free agents of the Kirk Ferentz era. Here are the top five!

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1. Colin Cole - undrafted in 2003 - There is no doubt that Cole is the largest free-agent money maker in the Kirk Ferentz era. Cole signed with the Minnesota Vikings as an undrafted free agent in 2003. He was eventually cut but then went on to play for five years with the Green Bay Packers. In 2009, Cole signed a five year deal with the Seattle Seahawks. He was cut after two seasons before resurfacing in Carolina. His estimated NFL earnings sit at $12, 654,662.

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2. Jason Baker - undrafted in 2001 - Baker punted for five NFL teams. The Registers says it was his accuracy that allowed him to stick around for 11 seasons. In 2007, the Panthers made him the highest-paid player in league history at punter. His estimated NFL earnings are $9, 981,500.

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3. Matt Tobin - undrafted in 2013 - Imagine that, an offensive lineman from Iowa surviving in the NFL. Tobin proves you don't have to be a high draft pick to make it. The right guard has been paid by several NFL teams, but his most successful stint came with The Eagles in 2015. His estimated NFL earnings - $4,376, 512

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4. Casey Kreiter - undrafted in 2014 -  Kreiter spent the first four years of his NFL career with the Denver Broncos. He is in New York in 2020 with the Giants, trying to win the long-snapping job there. His estimated NFL earnings - $2,685.962

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5. James Ferentz - undrafted in 2013 - After not getting drafted in 2013, the Register reports he was working at Randy's Carpets in Coralville when the NFL came calling. He ended up in Denver, and won a title, then headed to New England and won one there too. He started two games in New England last season. His estimated NFL earnings - $2,313,631.

In case you were wondering what Iowa Hawkeye football player overall has made the most money in the NFL in the Kirk Ferentz era, he actually just retired. Drafted in 2007 by the Baltimore Ravens, the Register reports that  Marshal Yanda made over $70 million in his playing career!