A’s rotation takes yet another hit

The A’s lost another starting pitcher Saturday as Ross Stripling was placed on the injured list with a strained throwing elbow, making him their fourth rotation arm to hit the IL this month.

Stripling was perfect through three innings in Friday night’s loss to the Astros, then allowed six runs in the fourth and failed to make it out of the frame.

Oakland called up left-handed starter Jack O’Loughlin from Triple-A Las Vegas, as well as reliever Tyler Ferguson. To make room for O’Loughlin in the 40-man roster, the A’s designated Brandon Bielak for assignment just three appearances after they acquired him from Houston in a cash deal earlier this month.

O’Loughlin appears on track to make his major league debut next time Stripling’s turn in the rotation comes up. The 24-year-old Australian joined the A’s organization over the offseason after six years in the Tigers’ organization. He has a 5.12 earned-run average and 38 2/3 innings pitched over 10 appearances (eight starts) in Las Vegas.

JP Sears, Saturday’s starter, is the only member of the A’s Opening Day rotation who is not on the 15-day injured list. Joe Boyle failed to record an out in his first rehab start Friday from a lower back strain, Paul Blackburn is sidelined with a stress reaction in his right foot and Alex Wood has rotator cuff tendonitis.

Ferguson made his MLB debut for the A’s earlier this season and has allowed four earned runs in 6 1/3 innings over six relief appearances at the top level.