Mengden (elbow) was placed on the 60-day injured list Saturday, Shayna Rubin of The San Jose Mercury News reports.
Mengden underwent arthroscopic surgery on his right elbow Wednesday that will require a recovery timetable of 6-to-10 weeks, and his placement on the 60-day injured list frees up a spot on the 40-man roster for Burch Smith, who was acquired from the Giants via trade Saturday. Mengden will likely work as a middle reliever once again for the Athletics once he's healthy.