Rafael Devers walking thin line in his approach at the plate

Devers heads to first with a RBI single in the ninth inning of Tuesday's game. Although he went into Tuesday with 13 home runs, he only had 10 walks and a .242 batting average.Barry Chin/Globe Staff

Rafael Devers has put together a strange season at the plate.

The Red Sox 26-year-old star has contributed in the power category, entering Tuesday tied for third in the American League in homers (13) while also posting a .498 slugging percentage.

Nevertheless, Devers is hitting just .246 with a .286 on-base percentage. Devers has never been an on-base machine. He’s known for chasing — and having success with — pitches outside the zone. It’s part of what has made him such a feared hitter.

But the low OBP is still certainly alarming.

“He hasn’t walked in months,” said manager Alex Cora Tuesday before the Sox’ 9-8 loss to the Reds at Fenway Park, a game in which Devers went 2 for 5 and drove in two. “So that’s part of the equation. Obviously, he’s an aggressive guy, but at the end of the day, you still have to control the strike zone. He’s run into some bad luck, too, but overall, I think he’s swinging a little more than usual, swinging at pitches that he usually doesn’t swing at. At the end of the day, those are tough pitches to hit.”

Devers not “walking in months” was an exaggeration by Cora. But it doesn’t feel like a hyperbole. Devers has just 10 walks on the year. His last free pass came May 9, tying the longest streak of his career without one.

What can get the All-Star slugger back on track? It’s not seeking out free trips, necessarily given Devers’s aggressive profile at the plate.

“I think in general, he’s a guy that’s never going to lead the league in walks,” hitting coach Pete Fatse noted. “I think when he’s at his best, taking his walks and guys are pitching around him, and things of that nature. So I think there’s a byproduct of simple things: being on time, getting efficient, gaining confidence.”

Hitting the ball hard and seeing results ultimately will help Devers fix some of his plate discipline woes. Devers appears as if he’s trying to do too much at the plate, leading to his 38.4 percent chase rate in his first 50 games.

“I think, at the end of the day, he’s one of the most feared impact hitters in our game,” Fatse said. “We’re trying to keep him in that mind-set. Obviously [walks] should be on his mind, but when he’s executing, doing damage, and impacting the ball, that’s the most important thing for me.”

Chang’s rehab derailed

Yu Chang was removed from his recent rehab assignment at Double A Portland. Chang had surgery to remove the hamate bone in his left hand last month and felt pain in the area when he returned to game action.

“He’s just sore,” said Cora. “There’s nothing structurally [wrong]. So we’ve just got to make sure he feels OK. Whenever he feels OK he’ll go out and play.”

Chang was at Fenway Tuesday for a workout.Julio Cortez/Associated Press

Chang was back at Fenway Tuesday, taking grounders at shortstop and batting practice on the field with the club.

Adam Duvall (right wrist fracture) played in a rehab game for Triple A Worcester at Louisville. He went 0 for 3 in a 5-4 loss.

Christian Arroyo (hamstring strain) will begin his rehab assignment with Worcester on Wednesday. The team will assess Arroyo’s progress at the end of the week.

Richard Bleier played catch for the first time since suffering left shoulder inflammation, while Alex Verdugo was sick and got the day off. Cora believes Verdugo will be ready Wednesday.