Manaea off to Stockton for rehab assignment

SEATTLE — Fewer than 10 months after left shoulder surgery, Sean Manaea is heading off on a rehab assignment, and barring any setbacks could be back in the rotation in several weeks.

Manaea, whose timetable was delayed a week or so by oblique soreness last month, is scheduled to pitch three innings with Class A Stockton on Monday. Minorleague rehabs are limited to 30 days for pitchers, so if all goes well he could be with Oakland by early August at the latest.

“He was our No. 1 guy last year,” manager Bob Melvin said. “He threw a nohitter early in the season and really, with all our starters, was the last guy to go down. It would be great to get him back. Boy, it would be a nice shot in the arm.”

On Sept. 19, Dr. Neal ElAttrache performed a procedure called a subacromial decompression and acromioplasty to create more room in Manaea’s shoulder capsule, cutting a

bone, the acromion area of the scapula, to do so. ElAttrache also repaired a small tear in the back of the shoulder labrum. The A’s had feared Manaea might miss the entire 2019 season, but ElAttrache called the surgery “a bestcase scenario.”

Manaea went 129 with a 3.59 ERA and he pitched a nohitter against Boston on April 21 at the Coliseum. When he was placed on the injured list in August, he said he’d been pitching with the shoulder problem all year, including during the nohitter.

Getting a top starter back for the stretch run would be big for the A’s, who lost potential AllStar Frankie Montas to an 80game suspension for violating baseball’s drugs policy last month. And Manaea is a popular figure in the club

house, with a buoyant personality and everchanging hairstyles, including his occasional “Samofro” and his recent Wolverinelike sideburns.

“He’s a very excitable young man,” Melvin said. “Loves to pitch, loves to be with his team. This is the start of a process that was delayed a little bit by the side thing he had, but he’s always been intent on giving us a couple of months this year, and hopefully that’s the case.”

Jharel Cotton will pitch for Stockton on Wednesday as he resumes his rehab assignment following Tommy John and hamstring surgery; he is still pointed toward Oakland’s bullpen upon his return.

Briefly: Mark Canha was a late scratch from Saturday’s game against the Mariners with back stiffness; Melvin said he hopes he will be in the lineup Sunday . ... AllStars Matt Chapman and Liam Hendriks will get to Cleveland via a sevenseat charter plane after Sunday’s game; Mariners AllStar Daniel Vogelbach is also booked on the charter . ... The A’s rotation coming out of the AllStar break is likely to open up with Mike Fiers, Brett Anderson and Chris Bassitt. ... J.B. Wendelken was recalled Saturday, the first day the reliever was eligible to return from TripleA Las Vegas, and starter Paul Blackburn, who had been called up Friday, was sent down.

Susan Slusser is a San Francisco Chronicle staff writer. Email: sslusser@sfchronicle.com Twitter: @susanslusser