Career
De Los Santos signed with the Texas Rangers as an international free agent in 2009. Initially a starting pitcher, the Rangers converted him into a relief pitcher in 2013. After the 2014 season, the Rangers traded De Los Santos and Chris Bostick to the Washington Nationals for Ross Detwiler.
De Los Santos began the 2015 season with the Harrisburg Senators of the Class Associate of Arts Eastern League.
The Nationals promoted De Los Santos to the major leagues on July 20. He made his major league debut the next day.
De Los Santos appeared in two games for the Nationals, before they optioned him to Harrisburg on July 25.