The No. 1 Red Sox starter likely is headed for the disabled list and their first baseman had to fly back to Boston yesterday to address a lingering illness.

Other than that, yesterday was a quiet day on the injury front.

Clay Buchholz was scratched from Tuesday’s start because of soreness from his right trapezius (neck) muscle. It’s enough that the club scrapped today’s planned bullpen session.

Buchholz has not pitched since last Saturday, meaning the club is fast approaching a point where it cannot afford to keep Buchholz on the active roster as an unused part.

The team let Buchholz know he could be DL-bound.

“Clay’s well aware of that and we had a chance to talk about where our threshold might be to make a decision and still, the bottom line being we’re not going to put him out there until we go through the normal build-up and make sure he’s in a safe place physically,” said manager John Farrell.

The AC joint in Buchholz’ collarbone is no longer an issue, said Farrell.

With Buchholz unavailable, the rest of the rotation can’t take advantage of Monday’s off day to gain an extra day of rest. Felix Doubront will start one of the doubleheader games on Tuesday. The club will need someone to start on Saturday in Detroit.

The other starter for Tuesday remains to be seen. Rubby De La Rosa, currently pitching out of the bullpen, and Pawtucket’s Alfredo Aceves are the two leading candidates.

First baseman Mike Napoli flew back to Boston yesterday to be examined by a club internist who hopefully will be able to diagnose why Napoli is experiencing symptoms such as light-headedness, grogginess and dizziness. He also felt nauseated shortly after he had to leave Thursday night’s game in the third inning.

A virus is passing through the clubhouse but nobody has experienced symptoms as long-lasting as Napoli’s, which is why the club was concerned enough to send him back home.