Luis Severino has been placed on the 15-day injured list because of a left oblique strain. The move is retroactive to Wednesday. Severino, a right-hander, recently pitched like the high-priced free agent the Athletics signed in the offseason. The A’s called up left-hander Hogan Harris from Triple-A Las Vegas. Severino signed a $67 million, three-year contract in December, the largest-ever for the typically low-spending A’s. He started the season slowly but improved significantly in his last five starts. Severino’s future with the team remains uncertain unless he agrees to an extension.