"I feel good," said Upton, noting that a stint with Class A Advanced Charlotte will be his first destination.
Manager Joe Maddon said that Upton was "doing well."
"He's really getting antsy," Maddon said. "He wants to get out there and do it. I think [head athletic trainer] Ronnie [Porterfield] wanted him to get about 25 or 30 at-bats.
"The big thing is to make sure his legs are well, that he's not going to get hurt running. And also throwing -- when you haven't run or thrown for a while, those are two big concerns, beyond just the fact that you're going to get your timing at the plate. So it's going to take at least that many at-bats or days to come back up here."
Maddon estimated that Upton's rehab stint will last approximately 10 days. He did not rule out having Upton join the team during the final stages of its upcoming three-stop road trip, but the manager made that scenario sound unlikely.
"We'll kind of do this almost like it's Spring Training all over again -- the beginning part, where you play sporatically every day, where you build up to the number of innings and at-bats," Maddon said. "That sort of stuff."
Maddon added that the most likely scenario would see Upton rejoin the Rays on April 20, when they start a three-game series against the Twins at Tropicana Field.