LOS ANGELES – Zach Eflin woke up a few days ago with a pain in the middle of his back. It officially became another pain in the pitching staff for the Phillies Friday afternoon when the 25-year-old right-hander was placed on the 10-day injured list.

He joined six other Phillies pitchers on the injured list and forced the team to make an adjustment in their starting rotation for their three-game series with the Los Angeles Dodgers.

“A few days ago, I just woke up with an extremely tight back,” Eflin said before the Phillies’ series opener Friday night at Dodger Stadium. “It was in the middle of my back on the right side and it was kind of hard for me to get up out of bed and walk around. I really never have experienced anything like this before, so it was a little different just waking up and having a decent amount of pain.”

The pain persisted long enough for the Phillies to take several precautionary actions earlier this week. One was to remove left-hander Cole Irvin from his triple-A Lehigh Valley start Wednesday after just three innings. Irvin replaced Eflin on the roster, but manager Gabe Kapler said he is not sure if the 25-year-old lefty will start Saturday night’s game against the Dodgers.

“Part of that is going to depend on how we use our bullpen [Friday] and part of that will be dependent on how we think the Dodgers may stack their lineup [Saturday],” Kapler said. “And then we’ll decide who gives us the best chance to win the game.”

Kapler’s other option besides Irvin is right-hander Vince Velasquez, who has pitched out of the bullpen in his two most recent appearances. Even though Irvin is a lefty, he might not be the better equipped pitcher to handle the Dodgers’ dangerous cast of left-handed hitters. Los Angeles’ first six hitters Friday night against right-handed starter Jake Arrieta were all lefties.

In his first three big-league starts, Irvin was far more effective against right-handed hitters, holding them to a .208 batting average and a .622 OPS. Lefties hit .353 with a 1.068 OPS against Irvin. Lefties have also hit .333 against Irvin at the triple-A level this season.

Velasquez, on the other hand, held lefties to a .260 batting average and .851 OPS. Those aren’t great numbers, but they may be good enough to get him his first start since May 6 when he gave up five runs on four hits and five walks in a start at St. Louis.

Kapler seemed to be leaning toward Irvin after the Phillies’ 6-3 loss to the Dodgers.

“I think what Cole gives us should we choose to go that route is a different look than the Dodgers have really faced much this year,” the manager said. “It’s just a different kind of tempo and different kind of pitcher and they’ve done damage against high-octane starters. That doesn’t mean we wouldn’t consider Vince, but Cole provides a different look.”

Losing Eflin certainly hurts because he has been arguably the Phillies’ best starter through the first third of the season, posting a 5-5 record and 3.02 ERA in 11 starts. He had not been as effective recently, going 0-2 with a 4.91 ERA in his last three outings. He also departed in the fourth inning of his last start at Milwaukee because of a stomach bug.

“Then two days later, I could barely get out of bed,” Eflin said.

The good news for Eflin is that he does not expect to remain on the injured list long. In fact, he expects to make his next start, which could come as soon as June 7 against the Cincinnati Reds at Citizens Bank Park.

“Two days ago it was pretty painful and today I was able to throw 90 feet, so it’s coming along really well,” Eflin said. “I just think we weren’t comfortable with me going out there [on Saturday] and risking doing something more when it could go away here in the next two or three days. Missing one start is not going to hurt.”

Eflin joined pitchers Edubray Ramos, Adam Morgan, Tommy Hunter, David Robertson, Pat Neshek, and Victor Arano on the injured list.