Ysla, 25, made 29 relief appearances for Double-A Portland this season, posting a 1-5 record with one save and a 5.05 ERA. He made 39 appearances in 2016 -- all but one at Portland -- and logged a 3.99 ERA with four saves.
A native of Venezuela, Ysla is 16-23 with five saves and a 3.85 ERA while striking out 374 batters in 359 2/3 innings. He originally was signed by San Francisco as an international free agent in September 2012.
To make room on their 40-man roster, Los Angeles transferred Adrian Gonzalez to the 60-day disabled list.