The ATH crew debates the Cubs' motives in acquiring José Quintana and whether it was a smart move. (2:29)

CHICAGO -- The Cubs and White Sox pulled off a blockbuster deal with the White Sox sending lefty Jose Quintana to their crosstown rivals for Cubs top hitting prospect Eloy Jimenez as well as top pitching prospect Dylan Cease.

The Cubs are also sending Class A infielders Matt Rose and Bryant Flete to the White Sox to complete the deal.

"It's the type of deal we've been looking to make for a long time," Cubs president Theo Epstein said. "It ended up being a surprising dance partner for us but I think a great baseball trade all around."

Jimenez, a 20-year-old outfielder, is the No. 5 prospect in baseball, according to ESPN's Keith Law.

Quintana, 28, is 4-8 with a 4.49 ERA this season after going 13-12 with a 3.20 ERA last year. And although his current ERA is the worst of his career, it is 2.43 over his past five starts -- and the White Sox won all five of those games.

The question is, can Quintana continue the surge? He has a career 3.51 ERA and fills an immediate and long-term need for the Cubs, who are short on starting pitching. They rank eighth in the National League in starter's ERA plus employ pending free agents John Lackey and Jake Arrieta.

While the Cubs needed starting pitching, they did not want a rental. Quintana is under contract through 2020, earning $8.85 million, $10.5 million and $11.5 million in 2018-20.

Epstein said that this trade wasn't made just for 2017. He wanted to optimize the window of offensive talent the team has for the next few years.

"Jose Quintana is probably more valuable to us at this moment in time than he is the White Sox," he said. "Our prospects at this moment in time are more valuable to the White Sox than us."

Quintana will make his debut for the Cubs Sunday in Baltimore.

"It is always extremely difficult to trade a person and player like Jose Quintana," White Sox general manager Rick Hahn said in a statement, "but difficult as it was, this deal moves us closer to our goal of building a team capable of contending for multiple championships over an extended period of time. Jose, our scouts and coaches throughout the organization deserve a tremendous amount of credit for his development from a minor league free agent signee to one of the most sought-after talents in the game."

After dominating the National League last season on the way to a World Series title, the Cubs enter the second half this season at 43-45 and 5.5 games behind Milwaukee in the Central Division.

Any more moves will depend on how the Cubs get out of the gate in the second half, Epstein said.

"This deal gives a chance to step back and survey the rest of the market," he said. "A lot will depend on how we play."

The White Sox are in last in the AL Central but have now made a series of trades that leave them with one of the best crops of prospects in baseball.

Jimenez is batting .271 with eight homers and 32 RBIs at high-A Myrtle Beach. Cease was 1-2 with a 2.79 ERA for Class A South Bend.

Hahn said the White Sox set a cutoff for what it would take to get Quintana and started taking offers.

"Ultimately, that yielded not only this offer we got from the Cubs but others we felt were above that line," he said. "But ultimately the Cub deal was far and away the most attractive given the potential impact of the prospects in that deal.

"Sunday morning, I reached out to Theo to express that I felt something was going to happen with Q in the coming days and to have a clear sense of what it would take for them, if they were interested, now was the time to engage. I would say that over the next 48 hours, things ramped up substantially. We officially agreed to the deal last night."

This is the first time the Cubs and White Sox have been trading partners since November 2006, when the White Sox sent Neal Cotts to the Cubs for David Aardsma and Carlos Vazquez.

The White Sox and Cubs haven't made a trade involving a former All-Star since 1992. The Cubs traded former AL MVP George Bell to the White Sox for Sammy Sosa and Ken Patterson.