Bellinger was named the National League's Most Valuable Player in 2019 and was part of the World Series-winning 2020 Dodgers team but struggled at the plate the last two seasons amid injury issues.
"We will miss you and the energy you brought to Dodger Stadium," the Dodgers wrote on Twitter. "Best of luck in Chicago!"
The Dodgers brought in righthander Syndergaard on a one-year deal, according to ESPN, though the team have yet to announce the signing.
Syndergaard hinted at the move by tweeting a GIF of 'The Dude' from the 1998 film 'The Big Lebowski' wearing a Dodgers hat with "YES!!!" written at the bottom.
The 30-year-old spent seven seasons with the Mets before signing with the Los Angeles Angels last offseason. He was dealt to the Philadelphia Phillies at the trade deadline last season and will now return to Southern California.
The Dodgers' NL West rivals San Francisco signed shortstop Carlo Correa to a 13-year, $350 million deal on Tuesday.
