Chicago Cubs president Theo Epstein, never known for his patience, refused to wait any longer Thursday, bursting past security and diving into the trade-deadline market as if it were a mosh pit.

The Cubs and White Sox jarred the senses when they made their first significant trade in a quarter-century, with the Cubs acquiring ace Jose Quintana from the White Sox for four prospects, including prized outfielder Eloy Jimenez and pitcher Dylan Cease.

“This is the type of deal we’ve been looking to make for a long time,’’ Epstein said. “In the end, it ended up being a surprising dance partner and a great baseball trade.’’

The last time the two teams talked a potential deal was in December when the White Sox were shopping Cy Young candidate Chris Sale. When Epstein telephoned White Sox GM Rick Hahn, and reigning MVP Kris Bryant's name was involved, it was a brief conversation.

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Yet the Cubs' package of four prospects - including outfielder Eloy Jimenez and right-hander Dylan Cease - represented the best return Hahn had seen in seven months of shopping Quintana.

And so the July trading period begins, kicking off the most fascinating period in the baseball industry.

It’s the time every club must turn over their cards and show their hand.

And the time we find out who really wants to win.

The blockbuster today certainly let everyone know the Cubs’ and White Sox’s intentions. The White Sox were desperate to move Quintana as quickly as possible - nearly trading him last week to another team - and now have the finest farm system in baseball with nine of the top 100 prospects. The Cubs needed immediate rotation help - and insurance for the future, with Jake Arrieta a free agent after this season.

They called the Detroit Tigers and asked for Michael Fulmer. Nope. Sorry, Chris Archer of the Tampa Bay Rays wasn’t available. The pricetag on Pittsburgh Pirates’ ace Gerrit Cole was too enormous. Oakland A’s pitcher Sonny Gray was too big of a gamble.

Quintana, a 2016 All-Star, was the ideal fit. Quintana, 28, who has pitched at least 200 innings the last four years with a career 3.51 ERA, is the eighth-best starter in baseball, according to the Cubs’ analytic department. And he’s their property through 2020, assuming they pick up reasonable club options after Quintana earns just $8.85 million next year.

“The reality is that this is deal,’’ Epstein said, “we were looking at over the long haul.’’

The bonus prize of the move is that if the Cubs didn’t get him, they might have been facing him. The first-place Milwaukee Brewers were deeply engaged in trade talks with the White Sox. It could have turned the Cubs, 43-45, from buyers to sellers if he went to Milwaukee, considering the Cubs trail the Brewers by 5 ½ games in the NL Central.

“We had a bad first half, and we have to own it,’’ Epstein said. “But we still have a good young core of talent. This group has won one World Series. Our goal is to win more.

“We needed to add starting pitching to make that happen.’’

The White Sox-Cubs deal could prove to be the sexiest trade one anyone makes at the trade deadline, but rest assured, there will be plenty more these next two weeks. There simply are too many teams still in contention.

The Washington Nationals, who sacrificed talented reliever Felipe Rivero for Mark Melancon of the Pittsburgh Pirates a year ago, must get a closer once again. They’re all in. Do they dare trade with the San Francisco Giants and take Melancon’s entire contract to bring him back to Washington? Do they give up money, along with top prospects for White Sox closer David Robertson? Or do they just go after San Diego Padres left-handed reliever Brad Hand, who’s striking out 11 ½ batters per nine innings, hoping that they don’t have to keep up this exercise year after year?

The Houston Astros, 60-29 with a 16 ½ games lead, are in the same wonderful predicament as the Cubs a year ago. They can play .500 baseball the rest of the season, go on a Hawaiian vacation, come back, and still win the AL West by 20 games.

Yet if they want to go where they’ve never gone in franchise history, and win a World Series, they’ve got to get another starter. They didn’t think that Quintana was worth the prospects the White Sox were commanding, and certainly not Francis Martes and outfielder Kyle Tucker. Still, they need another front-line starter to join Dallas Keuchel and Lance McCullers if they’re going to get by the Boston Red Sox and Cleveland Indians just to reach the World Series.

The White Sox, Miami Marlins and Oakland A’s have all declared their intentions: Sell. Sell. Sell.

Others have changed their mind. The Red Sox wasted months believing they were going to get third baseman Mike Moustakas of the Kansas City Royals, only for the Royals to play like it’s 2015 again. They Red Sox now have set their sights on Marlins third baseman Martin Prado and reliever David Phelps, along with Phillies reliever Pat Neshek and Giants third baseman Eduardo Nunez.

The Marlins are letting teams know that everyone is available for the asking price, but the truth of the matter is that they can’t unload big contracts without approval of the Commissioner’s office, while the team is being sold. And no one, Marlins officials insists, has even inquired about slugger Giancarlo Stanton and the remaining $295 million left in his contract.

The White Sox still are open for business, leaving no doubt that Robertson will be wearing a different uniform on Aug. 1. They’d love for third baseman Todd Frazier, and outfielder Melky Cabrera to be packing his bags, too.

The New York Yankees lead the pack of teams trying to figure out whether they want to play this high-stakes poker game. Do they shelve their rebuilding plans and go for the jugular, taking advantage of Aaron Judge’s sensational first half? Or do they just tinker with the roster as they did Wednesday, acquiring first base prospect Garrett Cooper from the Brewers for left-handed reliever Tyler Webb?

Do the Brewers, the surprise of the first half with their 50-41 record, stand pat and hope their lineup is strong enough to shock the NL Central? Or do they continue to search for another starter, especially after Quintana slipped through their hands>

“I’m curious as anyone what we’ll do,’’ Brewers All-Star closer Corey Knebel said. “It’s not up to us, but I’m hoping they see something.’’

The National League West, with the Arizona Diamondbacks and Colorado Rockies sitting in prime wild-card positions, will be just as fascinating to watch. If the D'backs knew before the season that Zack Greinke would have an All-Star first half, they would have been ecstatic, knowing his value would soar high enough to trade for prospects, and ridding themselves of his massive contract.

Yet, they’ve played so superb the first half, sitting with the second-best record, 53-36, in the National League, that Greinke can’t go anywhere. The D'backs won’t blow up their farm system, but they will grab a veteran reliever to assure they’re back in the playoffs for the first time since 2011.

The Rockies got this far with their prized rookie pitching quartet, and could be the most aggressive of the NL West teams. Don’t be surprised if they land All-Star shortstop Zack Cozart of the Cincinnati Reds for a short-term fix.

The Los Angeles Dodgers, who finished the first half with baseball’s best record, 61-29, winning 26 of their final 30 games, certainly could be intriguing. This team has been brilliantly constructed for the regular season, outscoring the opposition by a NL-record 163 runs before the All-Star break, and is on the verge of winning its fifth consecutive division title.

They finally have a tag-team partner with three-time Cy Young winner Clayton Kershaw in All-Star Alex Wood - the first Dodgers pitcher since Don Newcombe in 1955 to win his first 10 decisions.

Still, the question remains whether it’s enough, and if it's time for the Dodgers to finally sacrifice top-shelf prospects to reach the World Series for the first time since 1988. Now, that time has come again when they have the best team in the NL, but not enough to survive three playoff series.

History tells us the Dodgers won’t surrender blue-chip prospects, and will simply promote Walker Buehler, their Class AA star, who they refused to trade in Quintana talks. Still, the Dodgers and president Andrew Friedman are getting antsy to finally get out of the NL Championship Series.

“I felt like we were well-suited last year,’’ All-Star third baseman Justin Turner says, “but we fell two games short. We think this team is even better.’’

The most perplexing team may be Toronto Blue Jays. If it were simply up to Blue Jays president Mark Shapiro, they’d probably sell off their stars, and rebuild for the future. But this is a rich franchise that’s going to draw nearly four million fans, and, even as it sits in fourth place, still has the star power to reach the playoffs.

It’s a trade deadline, especially with Quintana now off the board, that will feature more depth than star power. There will be All-Stars you saw on TV Tuesday night who’ll be wearing different uniforms next week.

And there will be a whole lot of relievers trading places from coast to coast.

Stay tuned, baseball’s ultimate poker game is underway, and if Wednesday was any precursor, this one may be a doozy.

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