Houston Rockets center Alperen Sengun has agreed on a five-year, $185 million rookie extension, his agents Sean Kennedy and Jeff Schwartz of Excel Basketball told ESPN's Bobby Marks. The contract includes a player option in the last year.  The deal comes ahead of a 6 p.m. ET deadline for rookie extensions. Sengun becomes the first player to sign a five-year rookie extension and have a player option since Luka Doncic and Trae Young. Sengun, 22, blossomed into an All-Star candidate last season -- and earned a third-place finish in Most Improved Player voting -- by averaging 21.3 points, 9.3 rebounds and 5 assists per game for Houston before his season was cut short by an ankle injury.   He was one of just six players to average at least 21, 9 and 5 last season, with the others being Doncic,  Nikola Jokic, Giannis Antetokounmpo, Joel Embiid and Julius Randle. Sengun was taken with the 16th pick in the 2021 NBA draft by...