The Huntersville, N.C. native comes to the Wild Things after playing for the Kingsport Mets for two years. He was selected in the 19th round of the MLB Draft by the New York Mets out of the University of North Carolina-Charlotte. 

Rosenbaum posted a record of 3-7 in his first two professional seasons. In 2009, he went 1-3 with the Mets in 14 games with a 4.30 ERA and 18 strikeouts in 23 innings. On June 26, he pitched four innings, striking out four batters and allowing no runs. In 2008, Rosenbaum went 2-4 with one save. He had 41 strikeouts in 36 innings played with an ERA of 6.25.

At Charlotte, he went 5-2 with a 4.34 ERA while battling injuries in 2008. He was 9-1 in 13 starts in 2007, including 6-1 in conference play. He also was the winning pitcher in the A-10 Tournament Championship game that year.