O'Brien, 24, has registered two points (one goal, one assist) and 28 penalty minutes in 17 career games with the Capitals. The 6'1", 215-pound forward made his NHL debut on Oct. 9, 2014 against Montreal, earned his first NHL point with an assist on Oct. 14, 2014 against San Jose and scored his first career NHL goal on Oct. 26, 2014 at Vancouver.
This year with Hershey, the Halifax, Nova Scotia, native has three goals in nine games and ranks second on the Bears with 13 penalty minutes.
In 74 games with Hershey last season, O'Brien recorded 28 points (15g, 13a), ranked fifth on the team in goals and second in penalty minutes (118).
O'Brien has earned 111 points (56g, 55a) and 568 penalty minutes in 320 career AHL games with Hershey.
O'Brien signed with Washington as a free agent on Oct. 6, 2014 and re-signed on June 10, 2019.