Andrew Lopez of ESPN reported the news, noting Rubio practiced with the team Tuesday but is unsure if he will play in Thursday's scrimmage.
"I just had two practices so I have to talk with strength coach, [Suns coach Monty Williams] and the whole team," Rubio said. "I feel good but we have to be smart about it. It's a preseason game. We have to figure out a plan that's day by day. We can't plan ahead like other times. We didn't know when I was going to come so we have to play it day by day."
According to Lopez, the Suns are still without guards Elie Okobo and Jalen Lecque and big man Aron Baynes at the NBA's campus-like environment near Orlando, Florida. Baynes tested positive for COVID-19, while the other two are away for personal reasons.
As for Rubio, he said he is working his way back following the positive test and so much time away from the game.
"I'm good. I don't have symptoms," Rubio said. "Now that I'm back playing, after being out for three or four months, your legs feel it, your lungs feel it. That's something I have to work on and figure out how to give my best to the team and focus on my health too."
The point guard is averaging 13.1 points, 8.9 assists, 4.6 rebounds and 1.5 steals per game while shooting 41.2 percent from the field and 35.1 percent from three-point range this season. The three-point percentage is the second-best mark of his career, and he is third in the league in assists per game behind only LeBron James and Trae Young.
His Suns are 26-39 on the season, which is the worst record of all the Western Conference teams that earned an invite to the league's restart plan. They are six games behind the eighth-seeded Memphis Grizzlies.
Phoenix will need to make up ground in the eight seeding games, as any No. 9 seed that is within four games of the No. 8 seed will play in a play-in tournament for the final playoff spot. The No. 9 seed would need to defeat the No. 8 seed two times in a row in such a scenario.
Rubio's Suns are scheduled to play their first seeding game July 31 against the Washington Wizards.