The Kings agreed to send Robinson to the Houston Rockets along with Francisco Garcia and Tyler Honeycutt in exchange for Patrick Patterson, Cole Aldrich and Toney Douglas. The Kings, in the process of being sold, also received $1 million in the transaction.
Morris, averaging 8.6 points and 4.1 rebounds per game in Houston, will join his twin brother, Markieff Morris, in Phoenix.
The Kings will raise eyebrows by giving up so soon on such a high pick, but the move saves more than $3 million in payroll this season and reunites star forward DeMarcus Cousins with Patterson, his former Kentucky teammate.
Patterson, Aldrich and Douglas walked out of the Toyota Center just as Houston was starting its game against Oklahoma City on Wednesday night. The Rockets came into the game holding the No. 8 spot in the Western Conference and the moves were unexpected.
The 6-foot-9 Patterson had started 38 games for Houston this season and was the Rockets' fourth-leading scorer, averaging 11.6 points. Douglas was acquired in the offseason in a trade with New York and played in 49 games backing up Jeremy Lin. The 6-11 Aldrich, acquired in the James Harden trade with Oklahoma City just before the season, averaged 1.7 points in 30 games for Houston this season.
Sacramento had high hopes for the 6-10 Robinson, but he's disappointed so far, averaging only 4.8 points and 4.7 rebounds in 16 minutes per game.
Kings general manager Geoff Petrie had hinted that he'd only make minor moves before the trade deadline because of the pending purchase agreement that could move the franchise to Seattle next season.
Marcus Morris was all smiles about the deal on Wednesday night, even though the Suns entered their game against Golden State with the worst record in the West (18-36).
"It's my first trade," Morris said. "All I kept hearing was, it's a business. It happens. I mean, it does happen. I'm excited to see where my career can go from here.
Suns coach Lindsey Hunter wouldn't talk about the deal specifically, but acknowledged that Phoenix is building for the future.
"We're trying to get better," he said. "We're trying to build a foundation of something that we hope will last."
Information from ESPN The Magazine's Chris Broussard and The Associated Press was used in this report.