He made his debut in the FA Cup defeat to Morecambe. He managed to score his first goal for the club in a 2–1 away defeat against Port Vale, and after impressing manager Mike Newell in his loan stay, Proudlock was reported to be a target for the club in the January transfer window. Adam made his move to Grimsby a permanent one by signing for the club until the end of the 2010–11 season in January 2009. His strike partnership with fellow newcomer Jean-Louis Akpa Akpro resulted in Adam scoring a hat-trick against local rivals Lincoln City in a 5–1 victory on 7 March 2009. Following the arrival of loan striker Barry Conlon, Proudlock found himself playing second fiddle to him and Akpa-Akpro in the remaining games of the season, but his goals and performances were a great help in helping the club eventually stave off relegation from the Football League. Adam finished the 2008–09 season as the club's top goalscorer, with a total of 8.