It only made sense for the Arizona Diamondbacks to trade Paul Goldschmidt, who is one year from free agency and whose contract pays him just $14 million this year, making that year quite valuable in the trade market to any team looking to contend in 2019 and with an open spot at first base. The St. Louis Cardinals were a perfect trade partner, with surplus talent behind the plate and on the mound... [Kelly] could be a soft regular with just a little more contact in the air, but there’s above-average or better upside if he can improve that launch angle and get to the average or slightly better raw power that he has.
— Keith Law, ESPN
[The D-backs] goal is to accumulate solid players for the long term. This deal netted them an infielder (Andy Young), a solid pitcher (Luke Weaver), and one of the best young defensive catchers in the game (Carson Kelly). None of them were arbitration eligible this season. The Diamondbacks were able to shore up their system and their rotation while only giving up one year of Paul Goldschmidt.
— Audrey Stark, Beyond the Box Score
At the risk of being too blunt: the move makes the 2019 Cardinals a lot better and the 2019 Diamondbacks a lot worse. Over the last six seasons, among position players, only Mike Trout and Josh Donaldson have produced more wins above replacement than Goldschmidt has. St. Louis is boldly signaling its interest in contending next year; Arizona is signaling its interest in chasing the Padres for the 2021 NL West crown.
— Jack Dickey, SI
Diamondbacks: B+. While it has been difficult to know whether Arizona is serious about contending, this trade is a step in the right direction for the franchise... The truth is, this is probably the most Arizona was going to get for him... The D-backs also picked up a draft pick as a sweetener. Arizona does lose points for 1.) Trading one of the best players in all of baseball and 2.) Not getting a can’t-miss-type player back, but the truth is, it’s better to get volume as opposed to just one player in exchange for a 31-year-old on a one-year deal. Volume is what Arizona got, which makes the return difficult to debate. This trade works out for everyone. The Diamondbacks signal a potential new direction for the franchise as they pick up two prospects and a work-in-progress pitcher.
— Joe Rivera, Sporting News
Both sides did well in this trade... The Diamondbacks got two major league-ready starters, another decent prospect, and added another top-100 pick to their potential haul next season, where they will have eight picks in the top 100 so long as they don’t bring back A.J. Pollock. It has to hurt to see Paul Goldschmidt go, but this trade should accelerate the team’s window for contention even if they don’t go for it this year.
— Craig Edwards, Fangraphs
Diamondbacks trade grade: D. This package just feels too light to be enough for Goldschmidt -- even if it is just one season’s worth. Kelly has the chance to be a starting backstop thanks foremost to his defensive chops... The rest of the deal is where things fall apart for us. Without a high-grade cambio, it’s hard to see Weaver sticking in a big-league rotation for long. Young, meanwhile, has nice numbers but is considered more of an organizational player than a prospect worth keeping an eye on. Arizona has a good front office. It’s possible they see things we don’t with both Weaver and Young. But, from our perspective, it would’ve been nice to see the Diamondbacks get one more piece that was closer to Kelly’s level.
— R.J. Anderson, CBS Sports
It's a good and fair trade for both sides, several executives say, but it's tough on the #Dbacks fanbase seeing their heart and soul walk out of the door in classy Paul Goldschmidt— Bob Nightengale (@BNightengale) December 5, 2018
The allure of Carson Kelly: great glove, excellent makeup. If he hits -- he's got a good swing and is athletic -- he's a star. Luke Weaver was really good in 2017, mediocre in 2018. Trade may hinge on who he really is. I've heard from six front offices, and all love the return.— Jeff Passan (@JeffPassan) December 5, 2018
Immediate reaction from rival exec on #DBacks’ return for Goldschmidt: “A boatload” (Only he didn’t say boat). Five years control on Weaver, six on Kelly, plus pick in 70 to 75 range; Young fringy. #STLCards will call it a win, too. Kept Dakota Hudson, Kelly blocked by Yadi.— Ken Rosenthal (@Ken_Rosenthal) December 5, 2018
3 evaluators have generally said #Diamondbacks did not get 1 stud prospect back, but rather potential upside/control. But said considering 1b/31/1 yr to fr agcy the return was fine. 1 of evaluators was from NL Central said this: "But now I have to see Goldschmidt 19 times. Ow."— Joel Sherman (@Joelsherman1) December 5, 2018
A trade can never be accurately evaluated right after it happens, but this one looks great for both teams... [The Diamondbacks] will take a step back in 2019, but they knew they would need to retool with the departures of Corbin and Pollack, and other players approaching free agency as is Goldschmidt. They are currently handcuffed by Zack Greinke‘s contract, which accounts for 43.17% of the teams current payroll commitment heading into next year. Attempting a Greinke trade will be the next order of business. If they can do that, then they will be set up very well in the long run, but they hope to have just taken a big step towards long term success.
— DJ Kleinward, Last Word on Baseball