OAKLAND -- The A's have released starting pitcher Marco Estrada after less than one full season with the team.
Estrada, 36, has been on the injured list since April 17 with a lumbar strain. He made a handful of rehab appearances with various A's minor-league affiliates, but his long-lasting back issues have not gone away.
Estrada signed a one-year, $4 million contract with Oakland on January 25 and began the season as the team's No. 2 starter. However, the right-hander struggled in five outings, going 0-2 with a 6.85 ERA before being placed on the IL.
With Sean Manaea nearing a return and several other bullpen options ahead of him, Estrada didn't fit on the A's pitching staff, even in September when rosters expand. One of those bullpen options, left-hander A.J. Puk, was promoted to the majors on Tuesday.
Since Estrada was on the 60-day IL, his release does not open a 40-man roster spot, which remains full at 40.