By reaching an agreement on a new deal, Sanford will avoid an arbitration hearing.
The 24-year-old native of Salem, Mass. played in 60 regular-season games for the Blues in 2018-19, posting eight goals and 12 assists (20 points). In the Stanley Cup Final, Sanford recorded one goal and three assists in five games, including a goal in the third period of Game 7 to give his club a late 4-0 lead.
Sanford, 24, has played in 99 regular-season games in his NHL career, posting 12 goals and 16 assists.