Dan Haren may miss Wednesday start after back acts up

ARLINGTON, Texas -- Just when Dan Haren thought his back issues were behind him . . . they’re back.

The veteran right-hander tweaked a muscle in the right side of his back during his last start against Tampa Bay on Friday night. The injury is not in the same area as the lower-back tightness that sent him to the disabled list on July 4, but it is expected to prevent Haren from pitching Wednesday night against the Rangers.

Haren played long toss Monday and hopes to throw a light bullpen session Tuesday. “We’ll evaluate where he is after that,” Manager Mike Scioscia said.

Haren was effective in two starts after returning from the first DL stint of his career, allowing two runs and three hits in six innings of a 7-4 win over Texas on July 22 and one run and five hits in six innings of a 3-1 win over the Rays.

But on Saturday, “I was really sore,” Haren said. According to the pitcher, team physician Dr. Lewis Yocum “said it’s common for someone with lower-back issues to pull something down there.”

Haren, who has been getting four to five hours of treatment every day, said the discomfort “is nothing like it was before.”

If Haren gets pushed back, Garrett Richards will start Wednesday. Richards and Jerome Williams, who pitched four innings in relief Monday, were kept in the big leagues after Friday’s trade for Zack Greinke in anticipation of Haren’s next start being delayed. If Haren is pushed back, Scioscia said he “should be able to pitch shortly after” Wednesday.

Revolving door

Outfielder Mike Trout returned Monday after missing Sunday’s game because of a bruised left knee and hit a two-run home run and a two-run single in the Angels’ 15-8 win over the Rangers, but slugger Mark Trumbo, who tweaked a rib-cage muscle just under his right shoulder blade Sunday, was not.

Trumbo, who is hitting .304 with 27 homers and 69 runs batted in, hurt himself in batting practice Sunday but played, going hitless in three at-bats.

He could have played Monday, “but it’s probably better to get treatment and get ready for the rest of the series,” he said. “It’s more annoying because it limits your range of motion and the ability to turn your head and look at the pitcher.”

The concern for the cleanup batter is that the injury is in a sensitive area and could inhibit his aggressive swing.

“I take a pretty violent swing -- I’m up there to do damage,” Trumbo said. “With that, there will be trade-offs.”

Short hops

Shortstop Erick Aybar, on the DL because of a hairline fracture in his right big toe, hit in the cages for the second straight day and took grounders for the first time Monday. “It’s getting better and better,” Aybar said. Scioscia said Aybar should be ready to return for the series at Oakland beginning next Monday. ... Reliever Jordan Walden, out since July 14 because of a nerve problem in his neck, played catch for the third straight day Monday but appears at least two weeks away from returning.

mike.digiovanna@latimes.com