Armstrong will be recalled from Triple-A Columbus to serve as the 26th man for Wednesday's doubleheader against the Yankees, Jordan Bastian of MLB.com reports.
Armstrong will join the Indians ahead of Wednesday's twin bill to offer an extra bullpen arm. The 26-year-old owns a 4.76 ERA through 22.2 innings this season. While he's expected to return to the minors following the doubleheader, Armstrong will likely see another shot with the Indians after rosters expand in September.