Devin Booker is not happy with the Suns.

The 21-year-old guard is upset Phoenix waived Tyler Ulis on Saturday, according to a report from Yahoo Sports. Booker and Ulis were teammates at Kentucky and are close friends.

The Suns released Ulis, who has started 58 games over the last two seasons, in an effort to clear cap space, according to a report from ESPN.

Ulis was a rotation player for the Suns as a rookie after they picked him in the second round of the 2016 NBA Draft. He averaged 7.8 points and 4.4 assists in 23.4 minutes per game last season.

Booker has been one of the best young perimeter players in the NBA since he was drafted by Phoenix in 2015. He averaged 24.9 points and 4.7 assists in 2017-18. He is eligible to sign a five-year maximum rookie extension with the Suns this summer.

Phoenix reportedly signed veteran forward Trevor Ariza to a one-year, $15 million contract Sunday.