De Los Santos' contract was selected by the Guardians on Wednesday, Zack Meisel of The Athletic reports.
De Los Santos signed a minor-league deal with Cleveland in early December, but he'll now join the big-league club after several pitchers were placed on the injured list for an unspecified reason Wednesday. The right-hander has made four appearances at Triple-A Columbus to begin the year and has posted a 4.91 ERA and 1.64 WHIP in 3.2 innings.