The 26-year-old left-hander appeared in 31 games with the Mets from 2012-13. Carson was invited to Spring Training by the Angels in 2014 and finished the year in the Dodgers' system, posting a 5.40 ERA in 18 appearances for Triple-A Albuquerque.
Alexander, a 20-year-old outfielder, was a seventh-round pick in the 2012 First-Year Player Draft. He spent last season in the Rookie-level Pioneer League. He has a .233/.315/.357 slash line in 97 games of his three-year Minor League career.
Alden Gonzalez is a reporter for MLB.com. Read his blog, Gonzo and "The Show", and follow him on Twitter @Alden_Gonzalez. This story was not subject to the approval of Major League Baseball or its clubs.