Darrin is one of two Shannon brothers to play for the Buffalo Sabres. Older brother Darryl also enjoyed a long career in the National Hockey League
As mentioned, Darrin was drafted by Pittsburgh, however he never played with that team. Early in the 1988-89 season, while Darrin was still playing in Windsor, the Penguins traded their highly touted prospect along with solid defenseman Doug Bodger to Buffalo in exchange for disgruntled but often spectacular goaltender Tom Barrasso.
With a spectacular junior career behind him and having being traded for a high profile player, Shannon had immense pressure placed on him before he even entered the league. And for the first couple of seasons it appeared that he would not live up to expectations. He spent most of the 1989-90 and 1990-91 seasons apprenticing n the American Hockey League with the Rochester Americans. Aside from concerns about his skating, he seemed to lack confidence and assertiveness.
The Sabres gave up on Shannon after just one game in 1991-92. He was traded with Mike Hartman and Dean Kennedy to the Winnipeg Jets in exchange for Gord Donnelly, Dave McLlwain and a draft choice. He had played a total of just 55 games in Buffalo, scoring 10 goals and 14 assists for 24 points in his brief career.
In Winnipeg Darrin emerged as a solid player. He was a very good cornerman. He had good size and was able to shield the puck nicely. Once he retrieved the puck he did have the ability to make a play as suggested by his couple of 20 goal and 60 point seasons. While he never emerged as the power forward that scouts had hoped he would when he was drafted 4th overall, he nonetheless became a nice contributor in Winnipeg/Phoenix.
For all intents and purposes, Darrin's career ended prematurely due to reconstructive knee surgery in the off season of 1998. He missed the entire following season except for 10 games in the minor leagues. He would attempt a comeback in 1999-2000 by signing on with the Toronto Maple Leafs organization, but after 17 games in the minors he retired from the game.
Darrin played a total of 506 NHL games, scoring 87 goals and 250 points. It took longer than the Sabres had hoped, but he did mature into a nice NHL player.