Callahan was drafted by the New York Rangers in 2004 NHL entry draft in the 4th round as the 127th pick overall. He has played in 450 career games, all with the Rangers accumulating 132 goals and 254 points.
Callahan set career-highs during the 2011-12 season for goals (29), points (54), penalty minutes (61), power-play goals (13) and game-winning goals (nine).
The former Rangers Captain represented the United States at the 2014 Sochi Olympics and in the 2010 Vancouver Olympics where he won the Silver Medal.
Callahan has 11 goals and 25 points in 45 games this season.