Going into last offseason, the Chicago White Sox had failed to reach 80 wins in four consecutive seasons despite having three All-Star-quality players — Chris Sale, Adam Eaton, and José Quintana — on some of the most team-friendly contracts in baseball. Over the winter, GM Rick Hahn traded Sale and Eaton to Boston and Washington, respectively, for an outrageous stable of prospects. The top four White Sox prospects on FanGraphs’ organizational rankings — Yoan Moncada, Lucas Giolito, Michael Kopech, and Reynaldo Lopez — were all part of Chicago’s trade return, and Moncada ranked no. 1 in all of baseball.

On Thursday morning, Hahn offloaded his last big trade chip, Quintana, to the crosstown Cubs for another outrageous pool of prospects: outfielder Eloy Jimenez, pitcher Dylan Cease, and infielders Matt Rose and Bryant Flete.

The Cubs, whose title defense is on life support at 43–45, 5.5 games out of the division lead at the break, add a reliable no. 2 starter with three and a half seasons of team control to a rotation that’s on fire and careening up the runaway truck ramp. But the cost is considerable, and the inclusion of Jimenez shows just how dire things have become.

This offseason, Quintana was baseball’s most underrated starting pitcher. He didn’t put up gaudy strikeout numbers and, at 6-foot-1, with a normal-looking delivery, he didn’t stand out, particularly on a bad team that already had a more famous left-handed starter in Sale. But from 2013 to 2016, Quintana threw 200 or more innings every year, with an ERA+ between 113 and 126. From 2015 to 2016, he had a slightly better ERA+ than Sale did.

So far, 2017 has been Quintana’s worst year: Despite a career-high strikeout rate, he’s on track for career highs in ERA and walk rate. But since a rocky April, Quintana’s pitched much better, and he’s held opponents to a .213/.289/.333 line since June 1. That’s a good sign, because the book on Quintana isn’t that he’s occasionally great; it’s that he’s consistently good.

The Cubs could use consistently good. After ending 2016 with five qualified starters with an above-average ERA+, three of whom got Cy Young votes, the Cubs have only two starters with an above-average ERA+ this year: Kyle Hendricks, who’s on the DL and has nearly doubled his ERA from last season, and Eddie Butler, whom the Rockies left for dead five months ago.

Jake Arrieta (97 ERA+) and Jon Lester (99 ERA+) haven’t looked like themselves, and Brett Anderson (52 ERA+) and John Lackey (81 ERA+) are not only hurt, they’ve been so bad the Cubs might be better off if they didn’t come off the DL. Suddenly, and shockingly, considering where this team was nine months ago, pitching became an area of need. And even with Quintana, it still might be.

Since taking over the Cubs after the 2011 season, the front-office leadership of Theo Epstein and Jed Hoyer has liked to get its deadline-shopping done early, most notably in the July 2014 trade that sent Jeff Szamardija to Oakland for a package headlined by Addison Russell, and last season, when they acquired lefty Mike Montgomery from Seattle on July 20 and Aroldis Chapman from the Yankees on July 25.

By getting Quintana this early, the Cubs get an extra three starts out of him compared with if they’d made this trade on at the deadline. With the Brewers 5.5 games up in the division, the Cubs need every edge they can get. Even if they don’t overtake the Brewers (or, possibly, the Rockies, who are 7.5 games up in the wild-card race), the 28-year-old Quintana is still under team control through 2020 with two option years, the most expensive of which is for $11.5 million. As revenue grows, that might be backup-catcher money by 2020.

But making that trade now comes at a cost beyond Jimenez and Cease, the Cubs’ top two prospects. Trading so much for Quintana this early is a calculated risk that Quintana’s first-half struggles were a blip and not the new normal. Now the Cubs are more or less out of blue-chip prospects if they want to further improve their team without dipping into current contributors like Ian Happ.

By making this deal now, the Cubs can no longer wait out the seller’s market for starting pitching to turn into a buyer’s market. Coming out of the All-Star break, 13 of the 15 American League teams can talk themselves into being contenders, but that could change in a week, and a market of Quintana and Sonny Gray could suddenly be flooded with Gerrit Cole, Yu Darvish, and (if you want quiet consistency) J.A. Happ, with half as many potential buyers.

Epstein is the savviest baseball executive since Branch Rickey, so if he thinks Quintana’s his guy, I won’t spend too long second-guessing him. But the timing of this deal, and the inclusion of Jimenez, shows how heavily Epstein is betting on Quintana.

So what about Jimenez? He is a 20-year-old corner outfielder with a lanky but projectable 6-foot-4 frame. He’s already starting to fill out a body that will probably look like the Chrysler Building by the time he’s 25. You might remember him from the 2016 Futures Game, where he sacrificed his sunglasses on an acrobatic catch in right field, then took Rays prospect Ryne Stanek out off the Western Metal Supply Co. building. Nobody’s got Aaron Judge’s power, but Jimenez could end up in the next tier of gigantic man-beasts with the likes of Miguel Sanó and Joey Gallo.

After Gleyber Torres went to the Yankees in the Chapman deal, Jimenez was the Cubs’ last big prospect card to play. Not only was he a consensus top-15 prospect, but no other Cub ranked in the top 50 on the FanGraphs, ESPN, Baseball America, or Baseball Prospectus offseason lists.

Cease is another nice prospect with high upside, but only 120.1 innings under his belt in four professional seasons, thanks to Tommy John surgery during his draft year. Even considering how young the Cubs’ core is, Cease was always going to arrive too late to help this iteration of the team, and was therefore more valuable as a trade chip. Flete and Rose are organizational filler, and even though Cease has the potential to shoot up prospect lists as he proves he can not only get professional hitters out, but stay healthy, this trade is mostly about Jimenez.

The deal works for both sides. The White Sox now have four of the top 31 prospects in baseball, according to the BP midseason top 50, all of them acquired by trade in the past nine months, and Jimenez adds some balance to a farm system that, apart from Moncada, is pitching-heavy at the top. Hahn can still deal the odd reliever, or veteran free-agents-to-be like Melky Cabrera and Todd Frazier, but he’s now taken his three biggest swings, and hit on each one.

As for the Cubs, you’re not going to go broke trading prospects for good, relatively young, dirt-cheap big leaguers, and you could argue that the Cubs gave up less for three and a half years of Quintana than they did a year ago for three months of Chapman. But losing Jimenez is a big deal, and if the Cubs hadn’t underperformed so disturbingly in the first half of 2017, I doubt Epstein and Hoyer would’ve been in such a hurry to give him up.