Medeiros, 22, was selected by the Brewers in the first round (12th overall) of the 2014 Draft out of Waiakea (Hawaii) High School. He was rated No. 13 on Milwaukee's Top 30 Prospect list by MLB Pipeline and could fit as a starter or a reliever.
"We believe he has a chance to start," Brewers general manager David Stearns told reporters of Medeiros. "And I imagine the White Sox do, as well.
"This is the price of poker. You have to give up value in order to get value. We view Soria as one of the better available arms on the market this year, and he fits our team well."
Over 20 appearances (15 starts) for Double-A Biloxi this season, Medeiros is 7-5 with a 3.14 ERA, 107 strikeouts in 103 1/3 innings and a .234 opponents average against. He has allowed three runs or less in each of his past 10 outings (nine starts), going 3-3 with a 2.04 ERA, 64 strikeouts in 53 innings and just three home runs. Medeiros, who is 6-foot-2 and 205 pounds, is limiting left-handers to a .160 average (16-for-100), and opponents overall to a .188 mark (9-for-48) with runners in scoring position and two outs this season.
"Our reports show that we have a man who was a former first-round pick to be able to develop," White Sox manger Rick Renteria said. "I would imagine that we grab these guys with the hope and expectation that they are going to be able to evolve into something that will be able to help us here in the near future.
"Once they get into our hands, we will have a better idea. Hopefully, we have acquired some budding stars in the process."
Perez, 20, is 5-1 with a 2.01 ERA in eight starts this season with the Dominican Summer League Brewers. Soria posted a 2.56 ERA with 16 saves in 19 opportunities over 40 relief appearances this season. He was acquired with left-hander Luis Avilan and cash consideration from the Los Angeles Dodgers in exchange for infielder Jake Peter on January 4, a trade which has now turned into two more prospects.
Since May, Soria has allowed two runs over 24 1/3 innings, with 32 strikeouts and seven walks. He has benefited from dropping his arm angle during that time and is looking forward to joining a playoff push in Milwaukee.
"I enjoyed my time here," said Soria, who will join the Brewers on Friday in San Francisco. "I like the guys in here; the chemistry in here was really good. I always had fun with this group, but this is business and I'm going to a new team and new family. I'm going to try to get to the playoffs.
"That's what it's all about. This is our job, but at the end of the day, we are competitive people, competitive players and you want to win, you want to be part of a group that makes it to the playoffs and win their championship."