Adam Schefter explains the financial significance of Andrew Luck's new contract, especially as it relates to future deals for quarterbacks. (1:22)

Indianapolis Colts owner Jim Irsay stuck to his word and secured franchise quarterback Andrew Luck's long-term future with the organization before the start of the 2016 season.

The Colts announced Wednesday that Luck had signed an extension through the 2021 season that will make him the highest-paid player in the NFL, based on guaranteed salary.

Irsay announced the massive terms in a tweet:

$140 Million over 6 Years... Biggest Contract in NFL History... Congrats to #12!!! — Jim Irsay (@JimIrsay) June 29, 2016

The NFL's previous biggest contract was the five-year, $110 million deal the Green Bay Packers gave quarterback Aaron Rodgers in 2013. Last summer, the Seattle Seahawks gave quarterback Russell Wilson a four-year, $87.6 million extension that included $60 million in guaranteed money.

Sources told ESPN that Luck is guaranteed $87 million with this extension. The previous most-guaranteed money for any NFL player was $65 million for both Eli Manning of the New York Giants and Philip Rivers of the San Diego Chargers.

"I am thrilled and excited to continue with this great organization," Luck said in a statement. "I am thankful to the Irsay family and Mr. Irsay for providing me with this great opportunity and the trust that they've shown in me. I can't wait for this season to start."

The No. 1 pick in 2012 out of Stanford, Luck took the NFL by storm the moment he stepped onto the field. He made the franchise's transition from Peyton Manning a smooth one by leading the Colts to the playoffs in each of his first three seasons, reaching the AFC Championship Game in 2014 and claiming back-to-back AFC South titles.

Luck has the fourth-most passing yards (14,838) by any quarterback in his first four seasons in NFL history. He also is the fourth quarterback with at least 100 touchdown passes through four years, including an NFL-leading 40 in 2014.

But Luck isn't immune to struggles.

The 26-year-old is coming off the worst season of his four-year NFL career, completing just 55.3 percent of his pass attempts and committing 13 turnovers in 2015. He also showed he is not invincible. Luck missed two games early in the year due to a rib injury, and he missed the final seven when he suffered a lacerated kidney early in the fourth quarter against the Denver Broncos in Week 9. He also dealt with shoulder and abdominal injuries.

For months, Irsay had said he hoped and expected this agreement would be done around the Fourth of July holiday, if not before training camp. His goal now has been achieved.

"The organization is excited about getting this deal done and getting it done before the Fourth of July," Irsay said. "It's a big number. It was a deal that was a fair deal for both sides taking into account being cap friendly, being reasonable in the last year in 2021."

Luck was scheduled to make $16.155 million this season, the fifth-year option on his rookie contract.

The Colts report to training camp July 26 at Anderson (Ind.) University.

Richest Guaranteed Money Contracts Below are the top 16 contracts in terms of total guaranteed money: Name Pos. Team Amount Andrew Luck QB Colts $87M Eli Manning QB Giants $65M Philip Rivers QB Chargers $65M Ben Roethlisberger QB Steelers $64M Fletcher Cox DL Eagles $63.3M Joe Flacco QB Ravens $62M Russell Wilson QB Seahawks $61.5M Colin Kaepernick QB 49ers $61M Marcell Dareus DT Bills $60M Cam Newton QB Panthers $60M Ndamukong Suh DT Lions $60M Matt Ryan QB Falcons $59M Drew Brees QB Saints $55M Tony Romo QB Cowboys $55M Aaron Rodgers QB Packers $54M Jay Cutler QB Bears $54M Source: ESPN Stats & Information

Information from ESPN's Adam Schefter and Dan Graziano was used in this report.