Gargan made 54 appearances for the Galaxy since joining in 2014, adding four assists for Bruce Arena's men. Gargan was also a key member in the Galaxy's 2014 MLS Cup-winning team.
Gargan is joined by Ignacio Maganto, who spent large periods of the 2015 season at LA Galaxy II in the USL.
Maganto was drafted by the Galaxy in the 2015 MLS SuperDraft at the age of 23. Last season he played 13 matches, scoring one goal and notching two assists.
The moves see the Galaxy cut down two roster spots, with one more transaction rumored to be in the cards ahead of Sunday's MLS opener.
#LAGalaxy waive Gargan, Magnato. At least one more move coming before Sunday's MLS opener— Kevin Baxter (@kbaxter11) March 1, 2016