The 32-year-old Aguilar led the Marlins with his 15 home runs and 49 RBIs but he was hitting only .236.
With Miami losing 15 of 22 games in August and falling out of NL wild-card contention, Aguilar lost significant playing time to rookie Lewin Díaz. Garrett Cooper, who split time with Aguilar at first base and designated hitter, was activated from the injured list Friday.
"It didn't come as a surprise because Cooper and three guys can't be here," Aguilar said before the Marlins opened a four-game home series against the NL-West leading Los Angeles Dodgers. "I understand the move and I understand the business."
Aguilar signed with the Marlins after the Tampa Bay Rays released him following the 2019 season. The native of Venezuela was one of only five Marlins players who avoided the injured list during the pandemic-shortened 2020 season and helped Miami to its first playoff appearance since winning the World Series in 2003.
Last season, Aguilar had an NL-leading 93 RBIs before a knee injury sidelined him the final four weeks.
Aguilar said he hopes to find an opportunity with a contending team.
"We had talked to Jesús a bit ago about this and give him a chance to be on a playoff team," Marlins general manager Kim Ng said. "He's done a lot for this organization. These types of situations are never easy."
Aguilar began his career in Cleveland but flourished after he joined the Milwaukee Brewers in 2017. He set career highs with 35 homers and 108 RBIs in 2018, when he was an All-Star.
Midway through the 2019 season, the Rays acquired Aguilar in a trade.
"I just want to say thank you for the opportunity of being a Marlin for a couple of years," Aguilar said. "Hopefully, I can now go to one of the teams competing for a playoff spot."
Aguilar has hit .255 with 108 homers in his 11-year career.