The Padres received outfielder Manuel Margot, who was ranked No. 3 among the Red Sox prospects, according to MLBPipeline. Margot is regarded as the top piece in the deal, a player who could reach the big leagues in a year.
The Padres are also receiving shortstop Javier Guerra (ranked No. 6), left-handed pitcher (No. 25) Logan Allen and 2B/3B Carlos Asuaje (No. 23). All four are now among the Padres' top 20 prospects, with Margot the new No. 1.
Kimbrel, 27, converted 39 of 43 save opportunities this past season, posting a 2.58 ERA in 61 games. It was the first time in his career that his season ERA was higher than 2.10. His stay in San Diego, as it turned out, was a short one.
"When we made that deal, we felt we had a chance for Craig to be in San Diego for a long time," Preller said. "… But we knew if he came here and performed it could get to the point where if we wanted to turn around the asset, that we would be able to recoup a lot of value."
Moving Kimbrel also takes $11 million off the books for this season and $13 off for 2017. There's an option for 2018. But in the last two days, the Padres have trimmed about $18 million off their payroll.
That could mean more activity, Preller said, in free agency, as the team looks to add a left-handed starting pitcher, a left-handed bat to balance the lineup and, possibly, a short-term answer at shortstop to hold the spot until Guerra arrives.
"We do have some flexibility financially looking at the free-agent market," Preller said.
The Padres, who on Thursday traded setup man Joaquin Benoit to the Mariners for two Minor League pitchers, now have dealt their closer. What do the two deals do for their bullpen?
"We've created a lot of opportunity," Preller said. "There's a lot of ways to get to that spot. I think for a few guys on the roster, it's an opportunity to step up. We will be looking for guys to fill some big shoes."
Preller mentioned that the organization still has to make a decision on Brandon Maurer and if he'll remain in the bullpen, where he was successful in the seventh inning, or move into the rotation. He was previously a starter in Seattle in 2014.
As for the package of prospects the Padres received on Friday, it was considered by many in the industry to be a big haul.
"I think it's a good haul for the Padres," said Jim Callis of MLBPipeline. "The two prime guys they got, Margot and Guerra, probably already qualify as their two or three top prospects."
"They kind of reversed course. It seemed like last year they were going the other direction [trading prospects]."
A year ago, the Padres traded several Minor League players to get Major League returns -- Matt Kemp, Justin Upton, Derek Norris, Wil Myers and more -- as part of their roster renovation that, ultimately, led to only 74 victories.
In the last two days, the Padres made moves to help restock their farm system.
Margot, 21, hit a combined .276/.324/.419 with six home runs and 50 RBIs and 39 steals between Class A Advanced and Double-A. He played in 64 games in Double-A and could start there again, though many feel he can move quickly.
He was regarded by many to be the best athlete in the Red Sox system. Margot was the starting center fielder for the World Team in the Futures Game.
"In Margot, you get a two-year player [offense and defensive], tons of contact, up the middle, premium defenders. That's something we needed to add to the organization," Preller said.
Guerra, 20, hit .279/.329/.449 with 15 home runs and 68 RBIs last season at Class A Greenville. His power showed up for the first time as a pro in 2015 and he also hit 23 doubles.
"He's a shortstop who can flat-out play the position," Preller said of Guerra.
In Margot and Guerra, the Padres' future, in terms of being strong up the middle, got a big boost.
"Margot is a legitimate center fielder, plus-speed, advanced hitting skills," Callis said. "Guerra came in as more of a defensive shortstop, but then hit 15 home runs and opened some eyes with his bat. He has a chance to be a fine all-around shortstop."
Asuaje, who just turned 24 on Nov. 2, hit .251/.334/.374 with eight home runs and 61 RBIs in Double-A. He played second base, shortstop and third base last season and is a left-handed hitter.
Asuaje is likely the closet to the big leagues and Preller said he could potentially challenge for a roster spot in Spring Training, though he'll likely begin 2016 in Triple-A.
Allen, 18, was an eighth-round Draft pick in 2015 out of the IMG Academy, where he was a teammate with Padres third-round Draft pick Jacob Nix. He had a 1.11 ERA in eight outings with 26 strikeouts in 24 1/3 innings in short-season and at a Rookie League stop.
Preller said he that talked to about 10 teams in recent days about Kimbrel, and the Padres had several packages of players to consider. But with the Red Sox looking for a closer and having a deep farm system, it made for a perfect match.
"The Red Sox kept coming back as a fit," Preller said.
This isn't the first time the Padres have traded a superstar player to the Red Sox.