Mengden (foot) allowed two earned runs on four hits over 3.2 innings in Monday's rehab start with Triple-A Nashville.
Mengden was reaching optimal velocity throughout the outing, hitting 91-95 mph on the radar gun on a a consistent basis. The right-hander is likely to stay with Nashville after he's activated from the DL, but could receive a call-up down the line after making 14 starts for the A's last season.