The Sox acquired De Aza on June 3 after the Orioles designated him for assignment, sending Minor League pitcher Joe Gunkel and cash considerations over in the deal. De Aza hit .292 with a .484 slugging percentage in 60 games for the Red Sox, but the emergence of Jackie Bradley Jr. and the everyday presence of Rusney Castillo had quickly reduced him to a part-time role on a team looking ahead to 2016.
For the contending Giants, De Aza gives them an experienced player familiar with all three outfield positions and a knack for hitting right-handed pitching.
The 23-year-old Ysla, originally an international free agent signing of the Giants' in 2012, went 3-6 with a 6.21 ERA in 33 appearances (nine starts) for Class A Advanced San Jose this season. However, he flashed impressive swing-and-miss tendencies, averaging 10.7 strikeouts per nine innings. He excelled during his first two professional seasons, garnering All-Star honors in Class A and the Rookie-level Arizona League.
With rosters expanding Tuesday, the Red Sox will recall four players from Triple-A Pawtucket to their active roster: Outfielder/first baseman Allen Craig, catcher Sandy Leon and right-handed relievers Ryan Cook and Noe Ramirez.
Craig, 31, had spent nearly all of his season with the PawSox since being optioned there on May 9. He hit .274 with 14 doubles, four homers and 30 RBIs in 93 games at Triple-A. Cook, acquired from the A's before the non-waiver Trade Deadline, and Ramirez provide Boston with some sorely-needed bullpen depth.
Alec Shirkey is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.