We'll likely have more on the trade down the trade soon, but my first reaction is it being a good trade for both sides. Poveda has some promise, with a 13% K rate and 9.2% BB rate in AA last season. However, he's missing the entire season with Tommy John surgery, and in this stacked system, he's expendable. He was also using up a spot on the 40 man roster, and I imagine there was at least some question as to whether or not the Rangers should continue to protect him.
Reed has also pitched fairly well in 40 IP in AA this season, but was even more expendable in this system than Poveda. Neither puts much of a dent in the Rangers future, but both are nice return for the Marlins, who get something for Cantu, instead of nothing.
Cantu, meanwhile, helps the Rangers immediately. His weighted On Base Average is down to .313 this season, but he's managed to top .340 in each of the last two seasons. There's a good chance of him being at least a league-average hitter going forward. And while he's a defensive liability, he's probably a good bet to be at least mediocre at first, where the Rangers have gotten a combined .274 wOBA this season. Most importantly, Cantu is a righty, and while he's never displayed much of a platoon split in his career, letfty Chris Davis has (while also-lefty Mitch Moreland has displayed a reverse-split in the minors).
This isn't the kind of move that's likely going to turn the Rangers around, but it helps free up 40 man roster room, cost very little, is probably at least some improvement offensively and, at the very least, adds depth. Not exactly something to celebrate, but it should also be the first trade of this season that's met with near-unanimous approval.
What say you, Rangers fans?