An All-Star right-handed pitcher for the Newport Gulls in 2011, Prosinski will be returning to the Gulls starting rotation for the 2012 season. Prosinski was outstanding in seven appearances (five starts), in which he posted a 4-0 record and 2.16 ERA with 27 strikeouts in 33.1 innings of work, before being shut down midway through the season with an injury. Prosinski made just one relief appearance after July 15 last season.  

Prosinski, a First Team All Big East Conference selection, was dominant during his junior year at Seton Hall, finishing with an 8-3 record, 3.65 ERA and 69 strikeouts in 88.2 innings of work over 14 starts this spring.

Prosinski made 14 appearances, starting 13 games as a sophomore, compiling a 7-4 record with a team-leading 1.91 ERA and 56 strikeouts over 94.1 innings of work. Prosinski was 3-3 with a 4.04 ERA in 14 starts as a freshman. Prosinski has allowed just two home runs over 258.2 innings pitched in his collegiate career.