St. Louis did not elaborate, but according to a report by Newsday's Arthur Staple, three NHL sources confirmed St. Louis requested a trade last month.
The NHL Trade Deadline is March 5 at 3 p.m. ET.
The 38-year-old right wing comes off winning a gold medal with Canada at the 2014 Sochi Olympics but was originally left off the team by Yzerman, who served as GM for Canada.
St. Louis was added to the team when Lightning teammate Steven Stamkos wasn't cleared to return from a broken leg in time for the Olympics and had to give up his roster spot.
St. Louis has played all but 69 of his 1,037 regular-season games with the Lightning. He won the Stanley Cup with Tampa Bay in 2004.
Last season, St. Louis became the oldest player in NHL history to win a scoring title when he finished with 60 points in 48 games, and he ranks 12th in this season with 56 points in 58 games.