On July 4, 2012, Deunte was called up to replace Jesse Crain on the roster. He was sent down a few days later without making an appearance, but would return in September. Heath made his MLB debut with the ChiSox on September 1, 2012, against the Tigers in Detroit. He faced Prince Fielder and got him to ground into an inning ending double play on two pitches.
Deunte looks to get more major league playing time in 2013 and is a good bet to be in the bullpen mix.