The Indians put Cody Anderson on the 60-day injured list to make room for Maton on the 40-man roster. Anderson underwent elbow surgery, after he tore a tendon in his right forearm last month.
Maton will be sent to Triple-A Columbus. The 26-year-old has bounced back and forth between San Diego and Triple-A El Paso this season. He has a 7.71 ERA in 24⅓ big league innings. Maton posted a 2.89 ERA in 13 relief appearances in Triple-A.
Maton was drafted in the 20th round of the 2015 MLB Draft out of Louisiana Tech.