ANAHEIM -- The Angels locked up the game's premier defensive shortstop for the next five years on Thursday, but as Billy Eppler said, "This deal did not come without a level of pain."
In his first major move as the Angels' general manager, Eppler acquired renowned 26-year-old Andrelton Simmons from the Braves and paid a heavy price. In exchange, he parted with starting-pitching prospects Sean Newcomb and Chris Ellis, as well as veteran shortstop Erick Aybar. Newcomb is No. 19 on MLB.com's Top 100 Prospects list, Ellis was the club's No. 2 prospect, and Aybar has been very much the Angels' heart and soul for the better part of the past decade
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The Braves received an additional $2.5 million -- to balance out the 2016 salaries of Aybar and Simmons -- and the Angels also received Minor League catcher Jose Briceno, who was Atlanta's No. 25 prospect.
With Aybar a free agent after next season, and shortstop prospect Roberto Baldoquin seemingly a long way from being Major League ready, the Angels needed a shortstop beyond next season. They acquired the 2015 Wilson Defensive Player of the Year -- but they also used their two best prospects in a trade that didn't fill any of their current holes.
"I think when you have an opportunity to pick up a premium-position player -- more balls are hit at short than anywhere else -- you do it," Eppler said while stuck in a layover in, of all places, Atlanta. "The free-agent market, historically -- if you look in the past, if you look in the future -- does not generally offer a plentiful amount of shortstops. For our estimation, it was a supply-and-demand equation. It got to a point where it felt like this was an opportunity to grab something that very rarely presents itself."
Video: Gonzalez on Angels' acquisition of Simmons
Simmons has batted a subpar .252/.301/.357 since his first full season in 2013. But he's also compiled a Major League-best 94 Defensive Runs Saved since then, while leading the National League in defensive Wins Above Replacement (dWAR) in each of his three full seasons in the Major Leagues.
Simmons won the Rawlings Gold Glove Award in 2013 and '14, and he was just named Wilson Defensive Player of the Year at shorstop for the third consecutive time on Wednesday, in addition to receiving the overall award, regardless of position. In 2013, his 5.4 dWAR equaled the best single-season mark at any position in Major League history.
In other words, Simmons can pick it.
"Andrelton provides us up-the-middle foundation at a premium position for years to come," Eppler said in his initial statement. "To know we have a player with Andrelton's talents, drive and competitiveness at such a young age signed through 2020 is a vital step in adding to our core group."
Aybar was signed by the Angels out of the Dominican Republic in 2002 and emerged as one of the club's core leaders for the better part of the past decade. A tough, fiery competitor, Aybar won the Gold Glove in 2011, made the All-Star team in '14 and has batted .278/.318/.383 while averaging 144 games over the past seven seasons.
The trade caught Aybar by surprise.
"You see everything in baseball," Aybar said in Spanish. "I told myself after the season that I was going to be ready for whatever happened, but I figured I would at least finish off this year  with the Angels. It shocked me."
Eppler knew he was eventually going to need a replacement for Aybar, but he didn't necessarily prioritize shortstop when the offseason began.
Jim Callis' analysis of the trade
Eppler was made aware of Simmons' availability at the General Managers Meetings in Boca Raton, Fla. When he first engaged with the Braves on Tuesday, he didn't think the Angels stood much of a chance. But when Eppler awoke on Thursday morning, "It felt like we were approaching the red zone, and we were going to get close to maybe pushing this thing over the goal line. It really picked up a lot of momentum."
Video: Bowman on Braves getting Aybar, prospects from Angels
For rebuilding Atlanta, coming off a 95-loss season, Simmons represented one of few remaining pieces to help the Braves stock up on young players.
"I didn't expect it, but in the back of my mind, I had an idea there's a chance," Simmons said of the trade. "I'm happy to be part of an organization that's trying to win right now."
Newcomb and Ellis could both factor into a Major League rotation at some point next season.
Newcomb, who becomes the Braves' No. 1 prospect, was selected 15th overall in the 2014 Draft and jumped three levels in his first full season in the Angels' system. A 6-foot-5 lefty with a clean delivery, Newcomb finished with a 2.85 ERA and a 1.27 WHIP, walking five batters and striking out 11.1 batters per nine innings for both Class A levels and Double-A Arkansas.
Ellis, who enters Atlanta's Top 30 list at No. 9, had a 3.90 ERA and a 1.37 WHIP in 140 2/3 innings in Class A Advanced Inland Empire and Arkansas, walking four batters and striking out 8.4 per nine innings. The 23-year-old right-hander projects more as a back-end starter who could eventually eat innings.
The Angels refused to include Newcomb in prior deals, most notably before the non-waiver Trade Deadline this past summer.
Eppler called parting ways with him now "very difficult."
"It gives you a lot of pause, and it makes your stomach hurt a bit -- a lot, actually," Eppler said. "It's difficult to do, but in this day and age, teams are extremely thoughtful in trades. If you don't have a feeling of hurt, or don't have a feeling of pain, then it's probably too good to be true."
Simmons is set to earn $6 million in 2016, while Aybar will make $8.5 million. Over the next four years, Simmons will make $8 million, $11 million, $13 million and $15 million, respectively.
The move addresses the Angels' future, but does little for their present. They still have a hole in left field, with varying levels of need at catcher, third base, second base, utility infield and the back end of the bullpen. They could also choose to chase a front-of-the-rotation starting pitcher.
Angels' Top 30 Prospects list
Eppler no longer has many trade assets within his farm system, so he's expected to lean heavily on free agency the rest of the way. He doesn't seem to mind.
"I think when you have an opportunity to pick up an impact-level shortstop at the prime age of his career, you have to be very mindful of that," Eppler said. "You have to be willing to take that leap of faith."
Despite being a defensive wizard, Simmons is a marginal fantasy shortstop. His value gets a slight boost by joining a better lineup, but he will not make an impact in mixed leagues unless he reaches double digits in both homers and steals.
NL-only owners will appreciate Aybar's respectable batting average and double-digit swipes, but those in mixed formats will be looking for more counting stats than he can provide as part of a weak Atlanta lineup.
Newcomb will not be on the Opening Day roster, but he could affect mixed formats by the end of 2016. He has been able to compile strikeouts and limit homers in the Minors, but he will need to harness his control to take the next step.
Alden Gonzalez is a reporter for MLB.com. Follow him on Twitter @Alden_Gonzalez and Facebook , and listen to his podcast.