CHICAGO -- The White Sox are building a monster bullpen for October, while the Cubs are building for the future. That set the foundation for a blockbuster trade between the crosstown rivals on Friday.

Less than two hours prior to the 3 p.m. CT Trade Deadline, the Cubs shipped All-Star closer Craig Kimbrel to the White Sox in exchange for second baseman Nick Madrigal and right-handed pitcher Codi Heuer.

"Saying goodbye is always tough," Kimbrel said via Zoom. "But with that comes a great opportunity. And it's great ballclub on the other side."

The Kimbrel trade was one within a handful of impact moves made by the Cubs, who also parted ways with core stars Kris Bryant (Giants) and Javier Báez (Mets), along with righty Trevor Williams (Mets) and outfielder Jake Marisnick (Padres), for prospects. That wave of trades followed the decision to deal Anthony Rizzo to the Yankees on Thursday.

Kimbrel also heads to the South Siders one day after the Cubs also dealt setup man Ryan Tepera to the White Sox. Kimbrel, Tepera and Andrew Chafin (recently dealt to the A's) created a dynamic trio for the Cubs this season, and ended up netting a slew of players for the North Siders as they plan for coming seasons.

"It was definitely different," Kimbrel said, referring to the volume of trades. "It's something you don't see very often, especially with the number of guys in the last couple days. It's tough, because we all came here to Chicago, we had a purpose, we had a goal."

Madrigal, 24, is currently on the 60-day injured list due to a proximal tear of his right hamstring and will miss the remainder of the 2021 season. Come next year, however, the Cubs will be getting a high-contact bat with five years of club control.

In 54 games this season, Madrigal slashed .305/.349/.425 with just 17 strikeouts. The second baseman ranks first in the Majors in contact percentage (91.8%), contact rate inside the zone (98.6%) and swinging-strike rate (3.7%), among hitters with at least 200 plate appearances this season.

"We've struggled as a group with contact," Cubs president of baseball operations Jed Hoyer said. "To get a player like Nick Madrigal, he just really fits what we're trying to do going forward really well. I just love how he plays the game. I've loved how he played the game since college. I was envious of the White Sox to get a player like that."

Heuer, 25, has posted 39 strikeouts against 10 walks with a 5.12 ERA in 40 games (38 2/3 innings) for the White Sox this season.

Kimbrel, 33, has a 0.49 ERA with 23 saves through 39 appearances, in which he has struck out 64 of 137 batters faced. The eight-time All-Star, and baseball's active saves leader (371, which rank ninth all-time) will join Liam Hendriks to anchor a strong bullpen for the White Sox.

"I've met him over the years," Kimbrel said of Hendriks. "Seeing [him] at the All-Star Game this year, I got to talk to him a little bit. So, there's a little bit of a relationship there and I'm sure it'll grow over the next couple months."