NASHVILLE, Tenn. - The Arizona Diamondbacks felt that in All-Stars Paul Goldschmidt and A.J. Pollock they had a championship-calibreoffence. All they needed was some pitching.

In two bold moves, they got it.

First, the Diamondbacks finalized a $206.5 million deal with free agent Zack Greinke on Tuesday. Hours later they agreed to acquire All-Star right-hander Shelby Miller from the Atlanta Braves for overall No. 1 draft pick Dansby Swanson, outfielder Ender Inciarte and pitching prospect Aaron Blair.

"Our ownership stepped up in allowing us to get Zack Greinke. It puts us in a position to get better as a team, but we weren't complete. We needed an additional piece to our rotation," general manager Dave Stewart said Wednesday after the swap was completed. "We've got Goldy and we've got Pollock, our core group of guys, who last year really put on a good display of basebll.

"And quite frankly we think that it's time to try to take it to the next level," he said.

Arizona also obtained minor league left-hander Gabe Speier in the trade.

The Diamondbacks are going all-in one season removed from finishing with the worst record in baseball. Under new manager Chip Hale they went 79-83 this year, a 15-game improvement over 2014, with a strong core of young position players. The offence scored the second-most runs in the National League last season but the starting staff threw the second-fewest innings in the league and had a 4.37 ERA, 11th of 15 NL teams.

Chief baseball officer Tony La Russa and Stewart set out for dramatic change, and the moves they've made have thrust the Diamondbacks to the top of the NL West.

Greinke, the 2009 AL Cy Young Award winner, had the lowest ERA in the majors in 20 years, then opted out of his contract with the Los Angeles Dodgers. The 25-year-old Miller threw over 200 innings and had a 3.02 ERA for the Braves.

Miller should slot into the No. 2 spot in the rotation ahead of Patrick Corbin, Rubby De La Rosa and Robbie Ray.

"You're getting almost 800 innings out of your starting rotation, which should help our bullpen out," Stewart said. "The biggest part of our problems in our 'pen last year is we had to go there very often and ask them for a lot of innings."

The Diamondbacks might not be done yet. Stewart said he'd like to add to the bullpen. Adding more depth to the rotation could happen, too.

The retooling Braves acquired Miller from St. Louis before last season for popular All-Star outfielder Jason Heyward. They've now turned him into quite a haul of young players.

Swanson, a shortstop, was the top pick in this year's amateur draft out of college power Vanderbilt. He hit .289 in 83 at-bats in low-A ball and is already MLB.com's fourth-rated prospect at his position. He is seen as a top-of-the-order player.

Inciarte is a slick-fielding centre fielder who hit .303 and stole 21 bases in his second season. He's under team control for five more years.

Blair quickly advanced through the minor leagues in three years and could make his major league debut next season. A 2013 first-round pick, the right-hander was 7-2 with a 3.16 ERA for Triple-A Reno after a promotion from Double-A.

The Diamondbacks will also lose their No. 1 pick to the Dodgers as compensation for Greinke.

"I value the draft picks just as much as other ballclubs. I think the difference is if my gut tells me to do something then I follow my gut," Stewart said of losing three top draft picks. "Believe me, they're very highly regarded players, but three players do not make our future."

Atlanta got Speier from Detroit in the trade for Cameron Maybin last month. The 20-year-old Speier has a 2.34 ERA in 45 games — eight starts — over three minor league season. He made 33 appearances for Class-A West Michigan this season.