The deal was an interesting one becaue both were captains on their respective teams. St. Louis, at 38 years of age, is the reigning Art Ross Trophy winner. Last season he led the National Hockey League with 60 points.
However it seemed St. Louis's relationship was strained a little with Lightning General Manager Steve Yzerman because he was not named to team Canada's hockey roster originally at the 2014 Olympic Winter Games in Sochi despite putting up some excellent offensive numbers. Yzerman was also Canada's executive director in Sochi this past month.
St. Louis was named to the Olympic team eventually when it was announced that his Lightning teammate Steven Stamkos could not participate for Canada because of a broken leg.
This season, St. Louis had a team leading 29 goals, 32 assists and 61 points, while Callahan had 11 goals and 14 assists for 25 points.
The Lightning also receive a first round pick in 2015 and a conditional second round pick in 2014.