The Cubs have signed the 30-year-old Herrera to a minor league deal, they announced Thursday, less than a week after the White Sox designated him for assignment.
Herrera had allowed four earned runs in 2 1/3 innings across two relief appearances for the White Sox early on before being let go. He had a 6.14 ERA in 57 appearances for the White Sox in 2019.
Herrera will report to the Cubs' alternate site in South Bend. Left-hander Matt Dermody has also been assigned to South Bend.
With those two moves, the Cubs' 60-man player pool is now full.