By Alek Arend Freddie Freeman will not be the Braves’ first baseman on Opening Day. That position will now go to Matt Olson after the Braves and Oakland A’s agreed to a blockbuster trade on Monday afternoon. Oakland is sending 1B Matt Olson to Atlanta in exchange for a number of prospects. The Braves are giving up OF Christian Pache, C Shea Langeliers, SP Ryan Cusick and SP Joey Estes. “BREAKING: Atlanta and Oakland are in agreement on a trade that will send star first baseman Matt Olson to the Braves, sources familiar with the deal tell ESPN,” tweeted ESPN’s Jeff Passan. “Oakland will receive…