"What they did was unfortunate. You know, you're talking about very long prison sentences. They do not play games," he said of the Chinese justice system.
The three freshmen UCLA basketball players were arrested in China on shoplifting charges last Tuesday.
Among the arrested was LiAngelo Ball, younger brother of Los Angeles Lakers point guard Lonzo Ball. Cody Riley and Jalen Hill were also arrested.
The men were released on bail early Wednesday morning, but were required to stay in their Hangzhou hotel until the legal process is over, which could take days, weeks or even months, ESPN reported.
Xi was "terrific" in response to his request and has indicated he will intervene in the case, Trump said.
"Hopefully, everything is going to work out, and I know they're very grateful because they were told exactly what happened," he said.
Trump, who has branded himself as a tough-on-crime politician, seemed to concede the players' guilt, but said it's a "very, very rough situation with what happened to them."
Asked whether he expects the men to be released to the United States soon, Trump said: "I hope so. I hope so."