Estrada (back) was released by the Athletics on Tuesday, Martin Gallegos of MLB.com reports.

Estrada (back) allowed four earned runs on four hits and three walks while recording three strikeouts over three innings for Triple-A Las Vegas against Albuquerque on Friday.

Estrada (back) will make his next rehab start with Triple-A Las Vegas on Thursday, the Associated Press reports.

Estrada (back) struck out two in a scoreless inning for the Arizona League Athletics on Thursday.

Estrada (back) was transferred to the 60-day injured list on Tuesday.

Estrada (back) completed a 25-pitch bullpen session Saturday and relayed that he felt "OK" afterward, Susan Slusser of the San Francisco Chronicle reports.

Estrada (back) threw 15 pitches from flat ground Thursday and could toss a bullpen session as soon as Saturday, Martin Gallegos of MLB.com reports.

Estrada (back) completed a throwing session on flat ground Tuesday, Susan Slusser of the San Francisco Chronicle reports.

Estrada (back) has progressed to throwing at 75 feet, Susan Slusser of the San Francisco Chronicle reports.

Estrada (back) said Sunday that he's hopeful he'll be cleared to play catch at some point during the upcoming week, Susan Slusser of the San Francisco Chronicle reports.