It’s merely a precaution, Clay Buchholz insists, nothing to be alarmed by.

Still, it’s better to be safe than sorry.

And so, after sleeping awkwardly on his right side on the Red Sox’ trip home from Chicago late Wednesday night and irritating the acromioclavicular joint near his collarbone, Buchholz has been scratched from his start tonight against the Phillies at Fenway Park.

“Being as early in the season as it is, I want to make sure I’m 100 percent every time I go out there rather than 80, 85 percent and risk having this be something that’s going to linger,” Buchholz said after the Red Sox’ come-from-behind 6-5 victory over the Indians. “If it was September, I’d throw tomorrow. But it’s not. I’m going to take my time.”

In Buchholz’ absence, just-recalled right-hander Alfredo Aceves will face the Phillies.

Buchholz threw his usual between-starts bullpen session Saturday and said the twinge near his collarbone didn’t affect his mechanics or his arm slot. But he told manager John Farrell and pitching coach Juan Nieves about the issue, and everyone agreed to take a conservative approach, especially because Buchholz has spent time on the disabled list in each of the past three seasons.

The issue isn’t considered serious enough to necessitate an MRI or other testing, according to Farrell, and the Red Sox hope Buchholz will pitch later this week.

“There’s no real concern or harm to the throwing shoulder, but it’s irritating enough that he doesn’t feel 100 percent,” Farrell said. “Really precautionary, more than anything.”

Buchholz is 7-0 with a 1.73 ERA in 10 starts and would be on the short list of choices to start for the American League if the All-Star Game were held this month.

“That’s what’s hard about it,” Buchholz said. “I want to be out there every day. I think I’d be doing the whole team an injustice if I’m not 100 percent the whole year. That was the tough part.”