The Mets acquired Jackson from the Angels on Tuesday in exchange for Dominic Leone, Joel Sherman of the New York Post reports.
Double-A Rocket City placed Jackson on its temporary inactive list last Tuesday.
Jackson (oblique) was activated from the minor-league injured list Thursday.
Jackson was placed on Double-A Rocket City's 7-day injured list Tuesday due to an unspecified injury, Sam Blum of The Athletic reports.
The Angels announced Wednesday that Jackson (quadriceps) will be included on their Arizona Fall League roster, Sam Blum of The Athletic reports.
Jackson is out indefinitely with a significant upper quad strain, Kyle Glaser of Baseball America reports.
Jackson earned an invitation to major-league spring training Thursday, Fabian Ardaya of The Athletic reports.
Jackson joined the Angels' player pool Monday, Fabian Ardaya of The Athletic reports.