Carlo came to Kitchener after a strong year in North York playing bantam, he was a 2nd round pick behind Evan McGrath in 2002 by the Kitchener Rangers.  In September of 2003 DiRienzo became the youngest Rangers' netminder since David Belitski who was only 10 days younger when he stared for the Rangers in 1993, ten years before.  DiRienzo, joined an elite group which only includes two other underaged netminders in team history with David Belitski and Mike Torchia.

DiRienzo's rookie season much like that of Matt Harpwood and Scott Dickie did not start as planned.  The three goalies took part in a three-netminder carousel.  Each netminder would have to take their turn being a healthy scratch.  While this carousel was still spinning, DiRienzo accumulated a pair a shutouts, the only two of his career thus far.  A 3-0 victory in Sudbury followed by a splendid performance during a 7-0 Rangers' victory in Toronto.  In late November the Rangers were confident that they could use the underaged netminder as a backup and Matt Harpwood was traded to the Ice Dogs in exchange for Nathan O'Nabigon, a deal which would shape the championship team.

The Rangers completed a 21 game playoff run in 2003, and despite all of those games, DiRienzo remained on the bench for all contests.  With a sophomore season dawning Carlo was looking towards the future, of both his team, and himself playing a more prominant role with the Rangers'.  The playoffs came, but this time went fairly quickly, unfortunately for DiRienzo he only received one start, game #2 in Plymouth where he yielded 5 goals in a 6-3 loss.

Though it could be called a dissapointing season for the still young and potential-filled netminder, he did succeed in appearing in a total of 42 games, and put up a respectable 3.27 GAA in a very tough division playing for a team which was clearly inferior to the one that preceeded it.  Looking forward to his third season in the league, DiRienzo starts with a clean slate, with Brad Topping traded to the Windsor Spitfires and a second chance at the starter job infront of what should be a very strong Rangers' team.