"Chase is a very polished young pitcher coming off a very solid season at Double-A," Dipoto said. "We see him as a guy knocking at the door as a Major League starting pitcher."
The trade was the 14th made by Dipoto since the start of this past offseason and 40th in the 17 months since he took over the Mariners' front office, the most in the Majors in that span.
De Jong was rated the Dodgers' No. 16 prospect in 2016 by MLBPipeline.com. Entering the 2017 season, Jackson ranked as the Mariners' No. 12 prospect and Zabala as their No. 22 prospect.
De Jong, a second-round Draft pick by the Blue Jays in 2012 who was traded to the Dodgers in July 2015, has yet to make his Major League debut. He was the Texas League Pitcher of the Year for Tulsa last season.
Jackson, a 23-year-old shortstop, was a fifth-round pick out of Stanford in 2015. He hit .258/.332/.345 with six home runs, 47 RBIs and 16 stolen bases for Class A Advanced Bakersfield last year.
The 20-year-old Zabala is entering his fourth professional season. He pitched for the Mariners' Rookie-level Arizona League affiliate in 2016, posting a 2.88 ERA and one save in 25 innings over 16 relief appearances while striking out 28.
De Jong will join the Mariners camp on Thursday. He has pitched once for the Dodgers this spring, throwing two scoreless innings with one strikeout.
Freeman initially was scheduled to start the Mariners' Cactus League game Wednesday against the Indians, but he was scratched from the lineup. He had been competing for the utility infield role with Shawn O'Malley and Taylor Motter, but the Mariners now have seven days to trade, release or outright his contract to the Minors.
• Infielder D.J. Peterson is slowed by a sore leg and could miss a day or two, but the rest of players in camp haven't had any health issues to date.
• Mariners traveling secretary Ron Spellecy worked his final day with the club on Tuesday as he's retiring after 20 years. He'll be replaced by Jack Mosimann, who had been working as the director of Major League operations.
Greg Johns has covered the Mariners since 1997, and for MLB.com since 2011. Follow him on Twitter @GregJohnsMLB and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.