He plays as a Centre or Wing. Dineen made his debut against Treviso in October 2010. He scored his first try for against Ulster, also in October 2010.
He signed a two-year contract extension with in early April 2013.
In June 2015, it was announced that Dineen would be leaving.
He started for A in their 31-12 2011-2012 British and Irish Cup Final victory against Cross Keys, scoring "s second try. Dineen was added to "s 2012-2013 Heineken Cup squad in March 2013. Dineen made his European debut on 25 January 2015, coming off the bench against Sale Sharks to replace the injured Denis Hurley in Round 6 of the 2014-2015 European Rugby Champions Cup.
