Nickeas played four seasons in Major League Baseball (MLB) with the New York Mets and Toronto Blue Jays.

[4] In 2007, he switched his allegiance to Great Britain and played for the team in the 2007 European Baseball Championship.

He batted for a .202 average with five home runs and 24 runs-batted-in in 68 games, but Baseball America named Nickeas the best defensive catcher in the Rangers minor league system.

On May 26, 2012, Nickeas hit a grand slam at Citi Field, scoring Ike Davis, Vinny Rottino, and Kirk Nieuwenhuis.

On November 9, Nickeas signed a minor league deal with the Mets with an invitation to spring training.

[6] On December 17, 2012, the Mets traded Nickeas, R. A. Dickey, and Josh Thole to the Toronto Blue Jays for Travis d'Arnaud, Noah Syndergaard, John Buck, and Wuilmer Becerra.

[8] On August 8, 2013, it was reported that Nickeas has been hit with a pitch, resulting in a non-displaced hairline fracture on his forearm.

His contract was selected by the Blue Jays on September 3 after the Bisons season ended, and the major league rosters expanded.

[12] On March 9, 2015, it was reported that Nickeas had retired from baseball and gone back to school at Georgia Tech.