Buchholz left his start after allowing one run and two hits over five innings because of lower back tightness. He threw 81 pitches.
Buchholz said his injury got progressively worse after the second inning.
"It's a nagging back that's been the same since last year," the right-hander said. "I feel like I was in a better position tonight to come out a little early and not put anymore stress on my body than I had to. The way we're playing right now, nobody wants to go on the (disabled list). That was my first thought, I've got to get through five innings."
The Red Sox have a new starting pitcher arriving on Monday, when left-hander Andrew Miller is promoted from Pawtucket to face the San Diego Padres. Boston also has two off-days in a five-day span, the first next Wednesday, the other the following Monday.
The confluence of those circumstances may allow Buchholz to fulfill his wish not to go on the disabled list. At the same time, manager Terry Francona said he does not want Buchholz dealing with back issues for the balance of the season, and that he will be examined by the team's medical staff when the team returns home Friday.
"We certainly don't want him to go through the rest of the year like this,'' Francona said. "Not the way he's pitching, but having this thing linger. There's some days off coming up. We'll re-evaluate it."
Buchholz said the discomfort feels like a pulled muscle.
"Every time I tried to get out and extend a little bit more with just about every pitch, that's when I felt it," he said. "The last inning, I felt like I was compensating in my delivery for it. I think that's how you're going to get yourself hurt in other places."
Buchholz resisted the suggestion that there was logic that he shut it down until he is fully recovered.
"Not for me,'' he said. "I want to go out there and pitch. I don't want to take two weeks off for anything. Get back in the training room with the staff, help it any way they can. Check it out tomorrow, go from there.''
Meanwhile, Lowrie, whose left shoulder has been bothering him for nearly three weeks, may be headed for the disabled list after leaving Thursday's game in the first inning. Lowrie said he felt like his shoulder came out of the socket while striking out with the bases loaded against Rays left-hander David Price.
"It's sore,'' Lowrie said. "It felt like it slipped out. It wasn't out, but it felt like it came out and went back in.''
Asked if he thought he might have to shut it down, Lowire said: "I don't know. I've never dealt with this before.''
Francona said Lowrie would be re-evaluated by doctors back in Boston on Friday. Tim Britton of the Providence Journal, who was at Thursday night's Pawtucket game, said infielder Drew Sutton came out of the game in the seventh inning, which suggests he may be on his way back to Boston. Marco Scutaro replaced Lowrie in the bottom of the first and played shortstop, singling in three at-bats.
Lowrie has been bothered by what the team has called a bruised left shoulder since colliding with outfielder Carl Crawford in Detroit on May 27.
Thursday's strikeout extended Lowrie's hitless string to 0-for 15, and he is 1-for-17 on the trip. The Red Sox administered an MRI last week in New York, and both manager and player reported it came back clean, though Lowrie said the shoulder still ached.
Lowrie had three days' off (two games) before returning to the lineup Wednesday night and going hitless in three trips. In the 10 games since the collision, Lowrie is batting .163 (7-for-43), his overall average dropping from .306 to .270.
"It certainly wasn't this sore,'' Lowrie said. "I don't know what's going on yet, either. I just know what I feel.''
Information from ESPNBoston.com's Gordon Edes and The Associated Press was used in this report.