Hours before Opening Day, Padres' general manager A.J. Preller made one last blockbuster deal before the 2015 MLB season began - he acquired closer Craig Kimbrel from the Atlanta Braves. While it sounds favorable, was the trade a mistake?

Preller's monstrous offseason during which he revamped the dismal Padres' roster has perhaps had many fans believing he could do no wrong. However, while his latest deal brought arguably the best closer in baseball to the West Coast, it also cost the team a lot in terms of money and future value in their farm system.

The Padres were forced to inherit the remaining $34 million on Kimbrel's contract (through 2017) on top of outfielder Melvin Upton Jr.'s onerous deal that pays him $46.35 million over the next three seasons. But that's not all.

San Diego sent outfielders Carlos Quentin and Cameron Maybin to Atlanta, which was beneficial for the Padres, but they also gave up prospects Matt Wisler and Jordan Paroubeck as well as the No. 41 overall pick in the upcoming draft this June. According to Baseball America, Wisler was the Padres' top prospect and Paroubeck possesses considerable promise.

"Paroubeck has an athletic, 6-foot-2, 185-pound build and has plenty of room in his frame to add strength," Baseball America writes. "A switch-hitter, he has a loose, simple swing from both sides of the plate and has the tools to be an average hitter with above-average power potential. One executive said the now-20-year-old Paroubeck is a five-tool player who is raw but has upside and good makeup."

This has led to ESPN MLB Insiders Buster Olney and Keith Law to question the trade.

"The point I kept coming back to is how amazing it was that Atlanta could get rid of Melvin Upton's entire contract ... The Padres were so keen to get Kimbrel, that they were willing to take on Upton's entire contract, trade their best starting pitching prospect in Matt Wisler, the guy they were really not willing to part with in most previous deals this offseason, a minor league outfield prospect that has some potential and a draft pick ... Were they that concerned about the eighth and ninth innings that they were willing to do all of that just to get Kimbrel?" Law said on the Baseball Tonight Podcast on Thursday.

Olney apparently had a better alternative for San Diego:

"... you could have called the Phillies and made a much more efficient deal for Papelbon by simply working out of the vesting option and how much money the Phillies could have taken on for a closer who has thrown well the last couple years."

Although it's unknown what it would have taken to land Papelbon from general manager Ruben Amaro's grips, although previous rumors have provided a decent idea, we do know what Preller has given up this offseason. In the trades for Matt Kemp, Wil Myers, Justin Upton, Derek Norris, Will Middlebrooks, Shawn Kelley and Brandon Maurer, the Padres have surrendered the following players:

Catcher Yasmani Grandal

Starting pitcher Jesse Hahn

No. 2 overall prospect SS Trea Turner

No. 4 overall prospect SP Joe Ross

No. 6 overall prospect SP Max Fried

No. 9 overall prospect SP Zach Eflin

No. 10 overall prospect 2B Jace Peterson

No. 11 overall prospect RP R.J. Alvarez

No. 15 overall prospect 1B Jake Bauers

No. 16 overall prospect OF Mallex Smith

No. 12 and No. 41 overall picks in the upcoming MLB Draft

On top of that, they've inherited the highest payroll in franchise history. It's going to take time to see if these moves will pan out, but it appears that the Padres need to make the postseason in 2015 or else this offseason will be a bust and may cost them dearly in the future.