The centerpiece of the trade from Milwaukee's perspective is the 30-year-old Estrada, who has batted better than .300 with at least 70 RBIs in two of his three seasons as a starting catcher, first with Atlanta and then Arizona.
Estrada will bump 37-year-old Damian Miller, who battled a myriad of injuries in 2006, to a reserve role. Miller exercised a player option and will be in the final year of his contract in 2007. The Brewers likely will keep Mike Rivera and newly-acquired JD Closser for depth at Triple-A.
"I'm excited. It's an opportunity for me and I'm looking forward to helping turn them into a winning team," Estrada said. "It's exciting to be a part of building a winner."
Vargas, 28, was 12-10 with a 4.83 ERA for the D-backs last season and established career bests in wins (12), starts (30), innings (167 2/3) and strikeouts (123). He is three years younger but not as established as Davis, who made at least 34 starts and pitched at least 200 innings in each of the last three full seasons in Milwaukee.
Aquino will turn 29 in January and gives the Brewers another late-inning option in front of closer Francisco Cordero. Originally signed by the D-backs as a 16-year-old shortstop in 1995, Aquino has a 4.93 ERA in 111 relief appearances over the last three seasons. He served as Arizona's closer during the second half of that club's 2004 campaign.
"You can never have too much pitching," Melvin said. "I think we found that out last year."
Estrada and Vargas are eligible for salary arbitration and Aquino fell just short, according to Melvin. Milwaukee will have control of Estrada and Vargas for at least the next two seasons, and Aquino for the next four.
Davis is also eligible for arbitration and will be a free agent after the 2007 season. He was seeking a three-year contract extension from the Brewers, who benefited from the two-year contract extension they gave him in July 2004.
"I'm going to miss Milwaukee, but I'm definitely happy about the opportunity," said Davis, who has a home in the Phoenix area and was out of town on a fishing trip. "It will be nice to stay home during the season, and from what I know, [the D-backs] have a real good team and I'm hoping to help them out. I don't really know any of the coaches there, so I'm going to have to put on a happy face and just adjust as best I can."
Davis had already received a call from Arizona general manager Josh Byrnes and is still hoping for that multi-year contract.
"He didn't say much about it -- just, 'We'll talk,'" Davis said. "I'm hoping it will happen. I'd like to stay."
Melvin said it was tough to let Davis go. D-backs right-handed workhorse Livan Hernandez is the only Major Leaguer to make more starts than Davis over the last three seasons.
"We just weren't sure where the process was going to go [with Davis' contract]," Melvin said. "I like Doug a lot. He had a lot of success for us after we brought him in here."
Arizona also received a pair of players who may benefit from a change of scenery. Eveland is a promising left-hander and just turned 23, but he struggled in 2006 after a promotion to Milwaukee. He went 0-3 with an 8.13 ERA in nine games, including five starts as one of several replacements for injured right-handers Ben Sheets and Tomo Ohka. Eveland went 6-5 with a 2.74 ERA in 20 games for Triple-A Nashville.
Krynzel, 25, was Milwaukee's No. 1 draft choice in the 2000 First-Year Player Draft and is a fabulous defensive player, but he fell out of favor because his ongoing offensive inconsistency and an incident last winter in which he failed to notify the club of a serious injury suffered in a motorcycle crash. Krynzel eventually fessed up, underwent surgery to fix a broken collarbone and hit .231 at Nashville with a .314 on-base percentage. He was passed on the organizational depth chart by Tony Gwynn Jr.
Also on Saturday, reports out of San Francisco indicated that the Giants were close to a three-year deal with free-agent outfielder Dave Roberts, who reportedly had narrowed his choices to the Giants and Brewers. A call to Roberts' agent, John Boggs, was not returned before the Thanksgiving holiday.
"I haven't heard anything directly from his agent, but I know we offered him more money," said Melvin, who had a three-year offer on the table for the 34-year-old Roberts. "Guys know where they want to go, and John Boggs made it pretty clear that there was another club involved that made more sense for [Roberts] geographically."
Veteran center fielders Kenny Lofton and Steve Finley remain on the market, and Melvin left open the possibility of pursuing either player as a one-year bridge to Gwynn. The club also has Brady Clark and Gabe Gross under control for 2007, and both players have center field experience. The team also could simply decide to give Gwynn a shot.
Saturday's trade came a day after the division-rival Astros signed outfielder Carlos Lee for six years and $100 million, and six days after the Cubs handed Alfonso Soriano an eight-year, $136 million contract. Outfielders Gary Matthews Jr. and Juan Pierre have also netted huge free agent deals recently.
"We're going to have to do trades and build from our own system," Melvin said. "But I think we will still be in the running for free agents. The market is going to have to settle down at some point."