CHICAGO (AP) — The Chicago Cubs have acquired ace Jose Quintana from the White Sox in a major trade between crosstown rivals.

Trailing Milwaukee by 5 1/2 games at 43-45, the defending champions shook things up in a big way on Thursday by acquiring Quintana, a 2016 All-Star. In exchange, the Cubs sent four prospects to the White Sox — outfielder Eloy Jimenez, right-handed pitcher Dylan Cease, and infielders Matt Rose and Bryant Flete.

Quintana is 4-8 with a 4.49 ERA in 18 starts this season. He went 13-12 with a 3.20 ERA last year and made his first All-Star team.

All of the players the White Sox are either former or current South Bend Cubs. Cease, considered the #97 prospect in all of baseball by Baseball America, had a 2.79 ERA in 51.2 IP this season in South Bend. Jimenez considered the #14 prospect overall by Baseball America, batted .329/.369/.532 last season for South Bend with 14 homers and 81 RBI. Rose and Flete each spent a small part of 2015 and most of his 2016 season with South Bend. Jimenez, Flete, and Rose were playing for High-A Myrtle Beach this season.

95.3 MNC’s Tom Franklin contributed to this report.