A's manager Bob Melvin said Alvarez, who made a third go at a Minor League rehab assignment last week, is planning a visit with Dr. James Andrews. A second shoulder surgery could potentially be considered, though multiple MRIs have revealed no structural damage.
"I really feel bad for him," Melvin said Tuesday. "This is a guy that's worked so hard to get back with us and been right on the cusp a couple different times and had to go back and go through the rehab process again, which is very difficult to do, so my heart goes out to him."
Alvarez, 26, is under club control through the 2017 season, but a second procedure could keep him off the mound until 2018. The A's, then, could ultimately decide to not tender him a contract this offseason.
Though he never took the field with them, Alvarez has been a steady presence in the A's clubhouse while traversing multiple rehabs this season, sporting a positive attitude throughout. He's expected to return home within the next few days.
"He's a great kid, loves to pitch, always has a smile on his face, so it's really unfortunate the position he's in right now," Melvin said.
Seemingly little has gone according to plan for the A's this year: Alvarez was expected to slot behind Sonny Gray, who is also injured and iffy to pitch again this season. Even their depth has taken a hit, with Andrew Triggs (back) also not expected back in the rotation.
The A's have four other starters on the disabled list, and only left-hander Sean Manaea (back) is close to a return.
• The A's recalled infielder/outfielder Arismendy Alcantara on Tuesday, giving them a speedy option off their bench. Alcantara was 3-for-15 in his first three stints with the big league club this year.
Jane Lee has covered the A's for MLB.com since 2010. Follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.