Herrera had a seven-year period where he was one of the most effective relievers in baseball, having posted a 2.77 ERA with 454 strikeouts over 458 innings to go along with 60 saves from 2012-18. However, it quickly fell apart for him after he signed an $18 million deal with the White Sox before the 2019 season, and now he's decided to call it a career at the age of 31.

Herrera was signed to a minor league deal earlier this month and had been at the team's alternate training site. He's now been released by both Chicago franchises this month.  

Herrera was released by the White Sox after being designated for assignment on Friday. The right-handed reliever was signed to an $18 million contract by the club, but was a significant disappointment; posting a 6.54 ERA in 59 appearances with the club. Herrera has had success at the highest level, and if right, he could help in a middle-relief role down the stretch. 

Herrera was designated for assignment on Friday and is now officially a free agent after clearing waivers. It's possible he could find another team willing to give him a shot now that he can be had cheaply.