NFL Commissioner Roger Goodell has upheld Tom Brady's four-game suspension for using under-inflated footballs in the AFC championship game earlier this year, the league announced Tuesday.

In the 20-page decision, which can be read here, Goodell discovered that Brady asked an assistant to destroy his cell phone with "nearly 10,000 messages" in early March, on or around the same day the New England Patriots quarterback met with an independent investigator who was looking into the scandal that came to be known as "Deflategate."

"He did so even though he was aware that the investigators had requested access to text messages and other electronic information that had been stored on that phone," Goodell said. (Brady was under no legal obligation to cooperate with the investigation.)

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Brady and members of the Patriots' equipment management team were accused of knowingly using footballs that had been under-inflated in the AFC championship game against the Indianapolis Colts. After beating the Colts, the Patriots went on to defeat the Seattle Seahawks in the Super Bowl. Brady was named the game's MVP.

Brady's suspension was handed down in May, after an investigation revealed that he was probably "at least generally aware" that he was using improperly deflated balls. The team was fined $1 million and had two draft picks revoked. The Patriots did not appeal the ruling; however, Brady and his lawyers did.

The Patriots had no comment on Goodell's decision Tuesday, but the NFL Players Association has indicated it will challenge the decision, according to The Associated Press.

Unless the case goes to court, Brady will sit out the first four games of the 2015-2016 season, against Pittsburgh, Buffalo, Jacksonville and Dallas.