Over the last few days, we have taken a look back at the St. Louis Cardinals' significant trades of the offseason. So far, we've already broken down the Willson Contreras, Sonny Gray and Brendan Donovan deals. The last one — and the one that seemingly was the most difficult to get done — was sending Nolan Arenado to the Arizona Diamondbacks. Let's take a look back on the deal with the Cardinals sitting at 10-8 and Arizona sitting at 11-8. St. Louis Cardinals Haul Feb 26, 2021; Jupiter, Florida, USA; A general view of the St. Louis Cardinals logo on the stadium at Roger Dean Stadium during spring training workouts. Mandatory Credit: Jasen Vinlove-Imagn Images | Jasen Vinlove-Imagn Images The Cardinals received 23-year-old right-handed hurler Jack Martinez in return for Arenado and significant cash. Right now, Martinez is down with Class-A Palm Beach and has a 1.29 ERA in two starts. But the point of this deal wasn't necessarily what the club got back.…