A’s beat: Chapman leaves camp to get MRI on hand.

MESA, Ariz. — Matt Chapman, considered one of the major cornerstones of the A’s efforts to rebuild, left the team Thursday to get an MRI exam for right hand soreness.

“We don’t believe it’s serious,” general manager David Forst said in an email, without elaborating on the injury.

Chapman visited hand specialist Dr. Steven Shin at the Kerlan-Jobe Clinic in Los Angeles. Chapman is not believed to have incurred an impact injury nor a jammed wrist or hand; cortisone often is a potential option for hand soreness caused by repetitive activity.

Chapman has a history of left wrist soreness; he missed two weeks after injuring the wrist on a checked swing in April and he missed a month with left wrist soreness in 2015.

The 24-year-old third baseman is a superior fielder who hit .234 with 14 homers and 40 RBIs in 84 games last season.

Cactus League opener: Oakland’s Cactus League opener is Friday at Hohokam Stadium, and the lineup is set.

Franklin Barreto will lead off and play second, followed by designated hitter Matt Joyce, shortstop Marcus Semien, first baseman Matt Olson, right fielder Stephen Piscotty, left fielder Chad Pinder, catcher Bruce Maxwell, third baseman Renato Núñez and center fielder Jake Smolinski.

Núñez is out of options, so is an interesting case this spring. And Smolinski, going into his third full season with the organization, has a strong shot at a backup-outfield spot: Should Dustin Fowler win the everyday center-field job, as expected, the team would prefer a right-handed-hitting backup. Boog Powell is a left-handed hitter, leaving Smolinski and Mark Canha as the right-handed options. Smolinski, 29, is a much better center fielder. That’s key, with Fowler coming off surgery to repair a ruptured patellar tendon.

“We feel like there’s a significant talent level with him,” A’s manager Bob Melvin said of Smolinski. “You watch his swing, really if you’re trying to teach swing mechanics, he’s got that. He’s had times where he’s done really well, times he hasn’t and he’s been injured.

“We feel like there is more in there, it’s just about keeping him on the field. We feel if he’s able to stay on the field, who knows? He could gain some confidence and at his age, has the ability to be a really good big-league player . ... We’re looking at Smo pretty hard in that spot.”

Mengden, Blackburn ready: No. 3 starter candidate Daniel Mengden will be on the mound against the Angels on Friday. “I take it as just a normal start, try to get ready for the season,” Mengden said. “It doesn’t really matter in the grand scheme of things, I’m just trying to work on fastball command, throw some good breaking balls.”

Mengden went 3-1 with a 1.54 ERA and a .189 opponents average after being recalled Sept. 5, and this week, he was studying video of his bullpen sessions this spring with his work that final month of the season.

“I’m just making sure everything is syncing up right and everything looks good,” he said.

Paul Blackburn, who also put together a strong stretch last season after being called up July 1, will follow Mengden. Blackburn is working on a few things this spring: He changed the grip on his curveball and slightly changed the grip on his changeup. He plans to use both pitches more this year after using each pitch 9.3 percent of the time last season.

“Nothing too crazy,” Blackburn said of the changes. “I’ve seen a lot of progress with my curveball, so we’ll see where that goes. My main goal coming in was to get a better feel for my curveball and changeup and not throw my cutter as much, just throw it when I need it.”

Will the spiffed-up curveball be in action Friday against the Angels?

“Oh yeah,” Blackburn said. “I’m going full bore.”

Blackburn, who is from Brentwood, went 3-1 with a 3.22 in 10 starts before a line drive off his hand ended his season in late August.