OAKLAND, Calif. (AP) -- The beginning of July's first blockbuster trade occurred about a month ago, when Oakland Athletics general manager Billy Beane called Chicago Cubs executive Theo Epstein to ask about Jeff Samardzija and Jason Hammel.
Beane told Epstein he liked the starting pitchers, and he was going to be aggressive in an attempt to improve the AL West leaders. Fast forward to this weekend, when Beane proved just how serious he was during that initial call.
Oakland and Chicago announced the big trade on Saturday, with Samardzija and Hammel heading to the West Coast for a package of prospects that included the A's first-round selections in each of the past two drafts.
''The deal speaks for itself. To pick up two guys like that in early June is pretty fantastic,'' A's manager Bob Melvin said. ''We wanted more options and saw the urgency to get it done. This makes us better.''
The Athletics began the day with the best record in baseball, but Beane felt he needed to add depth to a rotation that responded well to season-ending injuries for Jarrod Parker and A.J. Griffin. Drew Pomeranz also is on the disabled list with a broken right hand.
Samardzija and Hammel join Scott Kazmir and Sonny Gray in one of the majors' best group of starting pitchers.
''We had to dig into our depth really early, and we felt like we needed two (starting pitchers),'' Beane said.
Samardzija will start for the A's on Sunday. He was scheduled to pitch for the Cubs Saturday.
In somewhat of a surprise, the A's sent left-hander Tommy Milone to Triple-A Sacramento later Saturday to make room for Samardzija.
Milone was 6-0 with a 2.62 ERA over his last 11 starts and 6-3 with a 3.55 ERA in 16 starts overall.
''What do you say to a guy like that?'' Melvin said. ''He's been terrific his last 10 starts and has meant a lot to us the last three years. I tried to figure out what to say to him. We haven't seen the last of him.''
Oakland will make a move Sunday to clear space for Hammel, who will start Wednesday.
Minor leaguers Addison Russell, Billy McKinney and Dan Straily went to Chicago in another painful deal for the lowly Cubs, who have played better of late, but are still last in the NL Central. Chicago also gets a player to be named in its latest July sell-off.
The Cubs lost at least 91 games in each of the previous three years. They traded away starting pitchers Ryan Dempster and Paul Maholm in July 2012, and Matt Garza and Scott Feldman last July.
''We certainly hope that this is the last year that we're obvious sellers at the trade deadline,'' Epstein said.
The key piece for Chicago in the deal with Oakland was Russell, a 20-year-old shortstop headed for Double-A Tennessee. A torn right hamstring sidelined the No. 11 overall selection in the 2012 draft earlier this season, but he was batting .333 in 13 games for Double-A Midland at the time of the trade.
Chicago and Oakland talked about a Samardzija for Russell deal, but Epstein said the one-for-one framework didn't work. He spoke with Beane on Thursday night, and that's when the trade grew into the larger package.
''We felt like Russell was a key for us in any deal with Oakland,'' Epstein said.
The hard-throwing Samardzija had a 2-7 record for the Cubs, but he also had a 2.83 ERA and 103 strikeouts in 108 innings, making him one of the most coveted pitchers on the market. The former Notre Dame receiver was selected by Chicago in the fifth round in 2006.
Chicago recalled left-hander Chris Rusin from Triple-A Iowa. Epstein said the Cubs were still discussing their options when it came to the rotation.
''I can say that (after that) it's going to stay the same until Tuesday for the doubleheader (at Cincinnati),'' Cubs manager Rick Renteria said of the rotation after Saturday.
Jake Arrieta is set to start Sunday in Washington and Edwin Jackson on Monday at Cincinnati.
The Cubs will add a 26th man, Tsuyoshi Wada, for Tuesday's doubleheader.
The Cubs talked to the 29-year-old Samardzija about a contract extension, but were unable to come to an agreement. He is set to become a free agent for the first time after the 2015 season.
''Jeff has been a bit of workhorse,'' Beane said. ''He's got a perfect health record. He's a guy that continues to develop. He's gotten better and better each year he goes out.''
Hammel signed a $6 million, one-year contract with Chicago in February and went 8-5 with a 2.98 ERA and 104 strikeouts in 108 2-3 innings with the Cubs. He pitched six-plus innings in a 7-2 victory over Washington on Friday.
Hammel, who turns 32 in September, also has three career postseason starts.
''He's gotten better and better and we think now is a great time to have him,'' Beane said.
The 19-year-old McKinney, who was selected in the first round a year ago, hit .241 with 10 homers for Class A Stockton this season. He is headed for Chicago's Class A affiliate in Daytona, Florida, where he will share the outfield with another top prospect in Albert Almora.
Straily finished 10-8 with a 3.96 ERA in 27 starts for the A's last year. He was sent down to Triple-A Sacramento after struggling earlier this season, and Epstein said he likely would be up with the Cubs after a short stay at Triple-A Iowa.
Even before the deal, Chicago had one of the richest minor league systems in baseball. The addition of Russell and McKinney just enhances the Cubs' impressive group of prospects.
''We think we have a real outstanding stable of good young position players that is a stable base to build off,'' Epstein said. ''We like how this positions us.''