LOS ANGELES — Joe Girardi said he first felt discomfort in his back when he was 26 years old and the pain has lingered ever since.

“But I played until I was 39,” the Phillies manager said. “It’s maintainable.”

The back spasms Bryce Harper felt this week were concerning, serving as a reminder that Harper’s back injury — which bothered him enough last September that he could not throw a baseball — has not gone away.

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But Girardi is confident that Harper will be OK.

“I think you get smarter as time goes on and you learn how to deal with it better,” Girardi said.

Harper did not play Wednesday night at Dodger Stadium after he woke up sore in the morning from the “little spasm” he felt Tuesday on a swing. Harper said he could have played, but the team wanted him to rest before Thursday’s scheduled off day.

He expects be in the lineup for Friday’s series opener in San Francisco. If so, Harper’s latest back injury will cost him just 14 innings. But it is the second time this season that the right fielder missed time because of soreness in his lower back.

Harper’s back discomfort is not expected to be completely alleviated. Instead, it is something the Phillies and Harper must learn to manage as they navigate the remainder of his 13-year contract.

“I don‘t think it will make Bryce tentative,” Girardi said. “I haven’t seen him really be tentative this year. I put my arm around him sometimes when he slides headfirst and I say, ‘Please don’t do that.’ It really hasn’t made him any more tentative.”

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The Phillies also played Wednesday without Jean Segura and Didi Gregorius, who are both on the injured list. Segura is out until at least July with a strained left groin. Gregorius was diagnosed this week with pseudogout, an arthritic condition in his right elbow, but could return next week as long as he rehabs this weekend with triple-A Lehigh Valley.

Segura was replaced Wednesday by rookie Luke Williams, who had three hits, and Ronald Torreyes continues to play shortstop for Gregorius.

“I always think it’s impressive when guys come up and don’t miss a beat,” Zack Wheeler said of Williams. “I said that earlier this year, too. It’s always impressive when you see that. He’s locked in out there. Guys filling in right now are doing a good job. You have Toe out there playing shortstop for a while now. He’s pretty solid, too. He’s a fun ballplayer to watch, those two up the middle. So, hopefully, we can get Jean back soon. We’ll go from there.”

Those two injuries are already significant, and missing Harper for an extended period would be another blow. He has missed 19 games this season with wrist, facial, and shoulder injuries along with the back problem. All signs point to him being ready Friday for a crucial series against the Giants.

“I think you know it’s unpredictable,” Girardi said of Harper’s back flaring up. “But it’s not like I sit around thinking, ‘Is it going to happen today?’ I just roll him out there and say ‘OK. Be good.’ Because even myself, it might pop up here and there.”

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Harper took six weeks off after the end of last season to rest his back and then worked five days a week with a personal trainer. He retaught himself how to throw from the outfield, believing his throwing motion was affecting his back.

He reported a day late to spring training so he could finish a training regimen in Las Vegas that was focused on his back. But the discomfort returned in April and forced Harper to miss a game. Girardi said then that “once you have some back issues, you’re always a little bit concerned about it.”

And that concern returned this week in California.

“There’s not a whole lot I can do. You try to keep him healthy,” Girardi said. “He works hard on it every day. He does his maintenance program. He does his treatment. I remember for myself, I could bend down and pick something up and it would grab. No rhyme or reason. So you just have to do the best you can.”