This trade seemed impossible for so many reasons. Would the White Sox and Cubs really pair up on a major trade? Would the Cubs part with their top prospect just a year after trading their previous top prospect? Would the White Sox trade starter Jose Quintana at all if his superficially poor start affected what teams would pay for him? Yet here we are, with Quintana headed to the Cubs in exchange for four minor leaguers -- two of whom, Eloy Jimenez and Dylan Cease, are top-100 prospects. Overall, I think the deal works well for both sides.

In Quintana, the Cubs get a pitcher who has thrown like a near ace for the past three seasons. After a rough start to 2017, Quintana has started to revert back to form over his last seven starts, although his stuff didn't really waver even when he was struggling. Signed by the White Sox as a minor league free agent before the 2012 season, Quintana went from high-A to the majors in just a few months, compiling just 48 innings of Double-A ball before Chicago promoted him. Since his arrival, he has delivered just over 21 WAR in five-plus seasons on the South Side, finishing among the AL's top 10 in ERA the past two years even with half his home games coming in hitter-friendly ... wait, I need to look this up ... (squints) ... Guaranteed Rate Field.

Quintana is a fastball/curveball guy primarily; the fastball sits in the low 90s with good life and plus command. He uses a changeup occasionally and has ditched the cut fastball he tried out earlier in his career. Generally pitching off his fastball, he had some bad luck and enough trouble locating his fastball in April and May that he started giving up homers and walks at uncharacteristically high rates, but without any evident loss of stuff.

But since he gave up seven runs (including three homers) in 2.1 innings against the Red Sox at the end of May, he has pitched more like the Jose Quintana of old. I don't think there was anything seriously wrong with Quintana to start this season, health-wise or mechanically, and he seems to be back to his established level of performance, which would make the Cubs two to three wins better for the rest of this year.

Quintana is under team control through 2020 -- including club options for 2019 and 2020 -- at what appears to be a maximum of $30.35 million for the next three seasons if the Cubs pick up both options. That's way below market value for a pitcher of his caliber. He solves their Jake Arrieta problem, too; it's been clear for a while that the Cubs don't intend to retain him beyond 2017, and given his performance this year, it looks increasingly like they've made the right call.

Quintana becomes the Cubs' ostensible No. 1 starter for 2018 and beyond, pushing Jon Lester and Kyle Hendricks into the 2-3 spots, although the team will probably end up acquiring another starting pitcher this winter for the back of the rotation.

The White Sox continue to rack up top-flight prospects as they trade veterans, landing Jimenez (the No. 5 prospect on my midseason Top 50) and Cease (another prospect from the back of my top 100) plus two throw-ins. Jimenez was hitting .271/.351/.490 in pitcher-friendly Myrtle Beach in high-A as a 20-year-old. He showed a mature approach for such a young hitter as well as the light-tower power he's had since signing for $2.8 million as a 16-year-old free agent in the summer of 2013. He projects as a middle-of-the-order bat who hits for power and gets on base at a high clip while playing solid defense -- maybe better -- in right field. If he were the entire return for Quintana, that would be totally reasonable for the White Sox.

Adding Dylan Cease gives them a lottery ticket to go along with the high-ceiling/high-probability Jimenez. Cease has one of the best fastballs of any minor league starter, regularly hitting 100-plus mph. He was at 95-98 when I saw him in March and flashed an above-average curveball and changeup. He lacks a consistent feel for both of those off-speed pitches as of now. This is his first year playing in a full-season league; he had Tommy John surgery right after signing in 2014 and spent the past two summers in short-season leagues, missing some time due to injury last year. His 13 starts and 51 innings this year are already career bests.

Cease is 21 but younger developmentally because of all the lost time, and although he has ace velocity, he lacks the movement or command for his pitches to play up as they should. He is a big upside play with a lot of risk -- health, reliever/starter -- and offers good value as the second piece in the deal. Cease came into 2017 as the Cubs' top pitching prospect, but he has been passed this year by Adbert Alzolay and Oscar de la Cruz (out with a pectoral injury), which likely made it easier for the Cubs to part with Cease in this deal.