Rubio, an unrestricted free agent, was coming off a Utah Jazz-friendly $14.9 million salary that ranked 15th among starting point guards in the league.
News of Rubio's move was earlier reported by The Athletic.
When healthy, Rubio was a mainstay in Utah's lineup, starting 144 of the 145 games in which he played over the past two seasons.
Drafted fifth overall by the Minnesota Timberwolves in 2009, the Spaniard holds career averages of 11.1 points, 7.7 assists and 1.9 steals over eight NBA seasons.
This past season, the 28-year-old Rubio averaged 12.7 points, 6.1 assists and 1.9 steals. But he admitted afterward that hearing his name in trade talks for Conley in February made things difficult.
"Yeah, I'm not gonna lie -- it affected me," Rubio told reporters, according to The Salt Lake Tribune. "We're [people] and we have feelings.
"I tried to stay as positive as I could and focus on the team and what we were doing here, but it's hard. A player like me, I play with heart, and you wanna go out there and play with heart, but you don't know if tomorrow you're gonna be here, so it's tough."
NBA free-agent contracts can't be officially signed until Saturday.