Buchholz threw 43 pitches at McCoy Stadium for Triple-A Pawtucket on Sunday and is scheduled to start on Saturday against the Rays.
Manager Bobby Valentine said he watched Buchholz throw 2 1/3 scoreless innings on Sunday, walking two and allowing one hit.
"He looked pretty much the way we needed him to look for those 40 pitches," Valentine said. "I'm glad he got his spikes wet in Triple-A, and he's confident that he'll be able to give us some length on the second game out [of the All-Star break], and so is the [coaching] staff."
Buchholz said he'll find a way to pitch against some batters during the All-Star break, hoping that by Saturday he'll be able to toss 80 or 85 pitches, working five or six innings.
"I got my break, so my body feels strong and healthy," he said.
Jacoby Ellsbury is also nearing a return. He went 1-for-4 with the PawSox on Sunday and Valentine said the center fielder is "getting pretty close."
Will Middlebrooks, who hasn't played since July 1 after tweaking his left hamstring but avoided a trip to the disabled list, was running around with ease and Valentine expects him to take the All-Star break off and return to action Friday against the Rays.
"Unless there's a major setback somewhere between now and then," Valentine said. "He looked really good running today. He did all his agility work, said he feels nothing."