Mengden was recalled from Triple-A Nashville on Monday, Julian McWilliams of The Athletic Bay Area reports.
Mengden will swap places with Sunday's spot starter, Chris Bassitt, who was sent to Nashville in a corresponding move. The right-hander figures to offer length out of the bullpen during the team's upcoming series against the Astros which starts Monday, though he could also be an option to start in place of the injured Sean Manaea (shoulder) on Friday if he goes unused in relief. Mengden, who was sent to the minors after a three-week stint on the disabled list with a sprained foot -- despite his serviceable 4.47 ERA across 16 starts with the A's -- compiled a 2.98 ERA across nine starts (45.1 innings) with the Sounds before being summoned back to the big club.