BOSTON — Luis Severino’s return to the rotation lasted all of one start.

The Yankees demoted the 22-year-old righthander Wednesday afternoon after he allowed five runs and seven hits over 4 1⁄3 innings of the Yankees’ 5-3 loss to the Red Sox Tuesday night.

Righthander Blake Parker took Severino’s spot on the roster.

“When we watched last night’s start, his fastball command was not great, his slider was somewhat inconsistent,” Girardi said.

Moreover, a changeup once a useful part of Severino’s arsenal was once again nonexistent, the case throughout the spring and earlier this season when he got off to a 0-6 start before losing his spot in the rotation.

The Yankees want Severino, who pitched well in three relief outings before earning Tuesday’s start, to improve his slider and fastball and rediscover his changeup.

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“I told him, ‘You need to force yourself to throw it . . . you need to force yourself to say, I’m going to throw 20 changeups today, I’m throwing 10 to righthanders and 10 to lefthanders,’ ” Girardi said. “I told him I don’t care about the results. I just want to see it get it better because if you can put it all together, we’ll really have something.”

Severino, not surprisingly, was disappointed.

“I was looking forward to my next start,” he said.

But the pitcher also acknowledged the obvious.

“It’s difficult be a starter with two pitches,” he said.

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Of his once-terrific changeup, Severino said the reason he’s abandoned it is simple.

“I’m not throwing it because I don’t have the same confidence I had three years ago,” he said. “I’m going to try and figure it out. I have to figure it out before I come back.”

Said Girardi: “I think to get through lineups a third time, which you want all of your pitchers to be able to do, and a kid with stuff like that, you need to have a third pitch . . . I really believe this is a short blip on the screen. I really believe he made a lot of progress before, but we need to see more.”