The 29-year-old Prado was signed by the Braves as an amateur free agent out of Venezuela in 2001, and debuted for them early in 2006, at the age of 22. After two and a half years of spotty appearances, he became a full-time player for Atlanta in the second half of 2008, and has been a permanent fixture ever since. Prado's natural position is second-base, but since the Braves acquired Dan Uggla from the Marlins after the 2010 season, Prado was moved to the outfield, where he started 91 and 111 games the past two years. However, in 2012, Prado also started at third base (20), shortstop (11), second base (8) and first base (4), so is truly a Swiss Army knife.
However, unlike most utility guys, Prado can actually hit Over the past five season, his line has been .296/.346/.438, which works out to a 110 OPS+. He was an All-Star in 2010, but both fWAR and bWAR said he had a better season last year, thanks to great fielding numbers. At the moment, he would seem to profile as the D-backs starting third-baseman, but it's not inconceivable to think that we could still also go ahead and trade Jason Kubel, and plug Prado in to left-field instead. However, that would leave Arizona with no obvious candidate to play regular third-base, unless you think Eric Chavez is the everyday answer, and he hasn't started more than 50 games there since 2007.
The key factor is that Prado is currently scheduled to be a free agent at the end of this season, and that's likely a good part of the reason why the Braves were willing to include him in the trade. They had apparently had talks with regard to an extension, but the player was apparently looking for something in the $11-12 million price-range - not impossible, given a market in which (as others have already pointed out) Shane Victorino gets $39 million for three years. If the D-backs end up losing Prado after one season, that will certainly put a different complexion on the deal, than if he is signed as a longer-term replacement, either at third or second.
Martin certainly seems to have been a much-loved component of the Braves, both in the clubhouse and among the fanbase, and there has been a constant stream of Atlanta fans, both here and on Talking Chop, talking about how much he will be missed. He gained a lot of respect for unselfishly moving out of second-base after the Uggla deal, drawing comparisons with the way that Chipper Jones made a similar move in 2002, to make way for Vinny Castilla. There seems little doubt that the D-backs acquired a good "character" guy, something that is certainly considered an important factor by GM Kevin Towers.
Another Latin American prospect, Delgado was signed as a teenager out of Panama, and in six minor-league seasons, has put up a 3.60 ERA with a K:BB ratio of 620:221 in 582.1 innings of work. He debuted for the Braves in June 2011, and put up solid numbers in seven starts, with a 2.83 ERA, though only picked up one win, with five no-decisions. He made 17 more starts for Atlanta in 2012, along with a relief appearance, and had a 4.37 ERA. He'll be under the Diamondbacks' control through 2018, so is definitely part of the longer-term future: he won't turn 23 until next month.
The pitch f/X data shows his fastball averages 93 mph, but he also throws a sinker with about equal frequency, a third of the time - that may explain why his numbers, particularly last year, skewed towards ground-balls more than average. The rest of the pitches are split between a change-up (21%) and a curve (12%) with a very occasional slider thrown into the mix. Coming in to the 2012 season. Delgado was ranked as the #3 prospect in the Braves' organization by Baseball America: the general feeling is that he can be pretty good, if he can avoid a tendency to walk too many people. He'll battle Tyler Skaggs and Patrick Corbin for the fifth spot in our rotation.