Players with such an injury historically require approximately 14 to 21 days to recover, which would put Booker's return during this first-round playoff series against the New Orleans Pelicans in question.
Pelicans coach Willie Green, who was on the Suns' staff last season when Booker played through a hamstring injury in the NBA Finals, has already warned his players to expect him back sooner, sources said.
Sources told ESPN on Wednesday that Booker would likely miss Games 3 and 4 against the Pelicans and that the Suns were still evaluating his MRI results to get a full picture of the injury and a clearer timeline for a return.
Suns coach Monty Williams said Booker didn't participate in any on-court work during practice Thursday and acknowledged how tricky a hamstring injury can be.
"You just have to wait and see how he progresses over the next whatever many days," Williams said. "If you've ever had one, you can feel really good until you start to do what NBA players are required to do, and then you're like, 'OK I can't do that as well as I want to.' So we have to wait and see."
Booker had 31 points in the first half of the 125-114 loss to the Pelicans in Game 2, but he didn't score in the third quarter. With 4:45 left in the period, he immediately asked for a timeout and went to the locker room after appearing to tweak his right hamstring as he was jumping to challenge a Jaxson Hayes dunk in transition.
The first-round series is 1-1 entering Game 3 on Friday in New Orleans.
Booker has had hamstring issues for the past two seasons. In November, he strained his left hamstring on a play similar to the one Tuesday and missed seven games. Last year during the NBA Finals, he suffered a hamstring injury in Game 3 but played through it and kept it a secret at the time. During the 2020-21 regular season, he also had a left hamstring injury and missed four games.
"Everybody has missed games except Mikal [Bridges]," Williams said. "We've been able to navigate those situations well this year. We know we can do it."
The Suns were 8-6 in games without Booker this season.
Paul said the Suns' season has been about next man up, and he credited Booker for making the trip to New Orleans when he could have stayed in Phoenix.
"I think he understands how important he is to our team," Paul said. "He lets us see everything he sees on the court and we'll go from there."
Added Ayton: "We need him. Just having that talk out there. Him pointing out things we normally don't see. From his perspective, seeing how the offense flows, seeing what the defense is giving us. Just keeping that energy and making sure we're always together, especially when we're on the road.
"It's the playoffs and it's gonna be loud. We'll need everybody. It's definitely going to be a relief to see him even though he's out for a little bit."
The Suns began the week as the clear-cut title favorites at +220, but after the Game 2 loss and Booker's injury, Phoenix is now co-favorites along with the Golden State Warriors. The Suns and Warriors are both +350 at Caesars Sportsbook, an ESPN partner.
ESPN's Adrian Wojnarowski and Andrew Lopez contributed to this report.