Houston Rockets guard Kevin Porter Jr. has agreed to a four-year, $82.5 million contract extension, his agent Sam Permut of Roc Nation Sports told ESPN on Monday.

The extension has a unique structure that allows for significant upside for Porter and protections for the Rockets. The deal's first season is guaranteed, and future seasons have several mechanisms to fully guarantee, sources said.

Porter, 22, landed the extension ahead of Monday's 6 p.m. ET deadline for players out of the NBA draft class of 2019.

Houston GM Rafael Stone and coach Stephen Silas have invested significant time and energy into Porter on and off the court, and his growth has given them reason to keep developing him as one of the franchise's young cornerstones.

While there have been unquestioned challenges in Porter's development -- including the Cleveland Cavaliers trading him to Rockets in 2021 for a late second-round pick unlikely to ever convey -- his extension offers him a chance to earn-out financially if he continues his growth into a fully reliable player.

One thing that's never been in question with Porter is his talent. He finished the 2021-2022 season strong for Houston, averaging 28.7 points, 7.3 rebounds and 7.4 assists in the final seven games, according to ESPN Stats & Information research. In that stretch, he had consecutive 35-point games, the youngest player in Rockets history to do so.

Porter showed significant improvement in his 3-point shooting a season ago, improving 6.5% to 37.5% -- the fifth-largest increase among 163 players to attempt 150 3s in each of the last two seasons, according to ESPN Stats & Info. His 48% on catch-and-shoot 3-pointers ranked him in the top five among players with at least 100 attempts, per Second Spectrum tracking.